knatten/cppquiz23

Repo for porting the questions on cppquiz.org to C++23

Porting CppQuiz.org questions to C++23

CppQuiz.org is an open source C++ quiz site. If you're unfamiliar with it, you can read more in its "About" section.

All the CppQuiz questions are currently targetting C++17. We need to update them for C++23. Most questions will still have the same answers, we just need to update the explanations and references to the standard. A few questions will also have different answers.

Doing this all by myself is going to take months, so I would very much appreciate some help from the community. You can also win a C++ book!

To make helping as simple as possible, I've created this repository containing all the questions. There is a directory for each question, named after the question number. That directory contains the source code of the question in a .cpp file, the hint and explanation in .md files, as well as a README.md explaining everything you need to do to port the question. There's also an issue for each question, making it easier to track progress. The issue has the same information as the README.md file.

As soon as we've updated all the questions in this repository, I'll import them back into CppQuiz, and from then on CppQuiz will always ask about C++23.

How to help

You can help by porting questions or reviewing pull requests:

Porting questions

First, fork this repo by clicking the "Fork" button at the top right.

If you're a collaborator in this repo, assign some of the issues to yourself, to avoid several people working on porting the same questions. A simple way to do this is to just find a page of unassigned questions, tick the box to select all the questions on that page, and assign them to yourself in one go. Don't worry if you can't finish them all, you can just unassign them later if it takes longer than you expected or you lose interest.

If you're not a collaborator in this repo, just port one question at a time and add a pull request, or ask @knatten to become a collaborator if you want to port many.

Then follow the instructions in the issue to port the question.

Reviewing pull requests

Pick an open pull request, check that the changes look good and that updated references are correct (point to the right place in the standard, quotes are correct etc.). Ask the contributor for changes if needed, otherwise comment "LGTM" in the pull request. I'll handle merging.

Other ways to help

• Look for questions labeled help wanted. It means the person responsible needs a second pair of eyes.
• Other ideas for help are also welcome, please get in touch (see Questions below).

Questions

If you have any questions, either file an issue in this repo, contact @knatten on Twitter, or email me at [email protected].

cppquiz23's Issues

Update question 207

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 157

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is unspecified / implementation defined

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 41

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: B

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 217

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 21

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 188

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program has undefined behavior

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 11

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 105

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: aAaA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 152

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 220

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: fhh

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 24

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 6

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 012012

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 12

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 44

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: YX

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 222

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 130

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: TS

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 177

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is unspecified / implementation defined

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 8

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: A

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 1

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 1

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 29

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 121

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 13

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: acbBCA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 135

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 13

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 115

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: d

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 197

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 12

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 226

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 1255

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 25

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program has undefined behavior

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 26

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program has undefined behavior

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 225

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 11422

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 161

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 5

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 3

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program has a compilation error

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 129

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program has undefined behavior

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 15

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: acabBA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 2

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 22

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 4

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 21

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 9

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 428

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 14

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: abcBCA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 195

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 163

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 0

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 159

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 34

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 35

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 12

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 18

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: B

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 16

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: abBA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 205

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 10

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 28

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: AABCBC

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 184

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: d

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 27

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: B

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 5

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: BA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 145

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 13

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 17

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: abBA

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 132

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: 11

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.

Update question 7

Thanks for helping!

Thank you for helping to port this question from C++17 to C++23.

You'll find the source code in question.cpp, this should normally not need modification.

In C++17, the correct answer is:

The program is guaranteed to output: A

Please verify that this is still correct in C++23. If it is, please do the following:

• Update explanation.md:
  • Refer to the correct section numbers
  • Use updated quotes from those sections (the wording might have changed)
  • Make sure the rest of the text in the explanation is consistent with the new standard
• Update hint.md if needed (usually not needed)

Note that some older questions are missing references to the standard, we don't need to fix that now.

If you get stuck, please describe the problem in detail in a comment to the issue, and a maintainer will add the help wanted tag so others can chime in.

If the correct answer has changed from C++17 to C++23, you can either just leave a comment in this issue, or see the instructions for updating meta data.