amartya-dev/go-learning

A repository with basic programs in Go lang

GoLang

Intro

• Designed as a system language.
• Can now be used as a general purpose language.
• Automatic garbage collection, memory clearing etc.
• Only ~25 keywords.
• Cross platform.
• Compiled language.
• Strongly typed.
• Supports type inference (can infer the variable type from declaration).
• Case sensitive

Variables and Constants

Declaring and Initializing variables

• Variables are statically types, a string remains a string for its lifetime
• var is used for declaration at package level, they can also be grouped together
• Go always initializes variable with zero value
• reflect can be used to check types
• Go can infer types from declaration
• Type conversion is pretty much like python
• Variables declared at package level are Global variables
• := works only inside functions and only if we're initializing the variables at the same time we declare them.
• It is necessary to use all the variables, it is not possible to declare variables without using it inside functions. If we declare a variable inside a function it is necessary to use it.
• := is used to declare new variables whereas = is used to reassign values or simply assign values to a variable
• Constants are immutable, declared with const, cannot use := with constants.
• Environment variables are accessible with os package

Pointers

• Go passes arguments by value, and not by reference.
• When we create a variable, Go creates a space for it in the memory, when we pass this variable into a function, it makes a copy of this variable with same value in different memory space, the changes are thus made only to the copy of the variable.
• & gives the memory address of a variable (the pointer value)
• & references a pointer and * de-references a pointer
• We can use pointers to pass value by reference

Conditionals

• If accepts some statements also before the boolean expression
• Any variables declared with if exist in only that if and else if blocks and are garbage collected after that
• Even the switch statements can accept statement declaration just like the if statement.
• The default statement in the switch can go anywhere.
• The switch case has automatic breaks, it stops the execution after a case match
• The fallthrough statement executes the next case also.
• The case can help match multiple statements