lisaolson/functions-training

fill in the internals of JS functions (with Math object)

Lisa Olson - Javascript Functions

Link to repository

https://github.com/lisaolson/functions-training

Summary

I had quite a hard time with these functions. The first few were fairly easy, but still more difficult than I expected. The last one I'm still confused with even after looking at the Solution file. I feel pretty confident writing For loops now and definitely more confident with functions in general, but I need more practice.

1. Build your own concatenation

Return a new string that is the combination of two arguments passed into the function

Example: dog and house will display doghouse

function combineWords(word1, word2) {
	// TODO: Place your code here
}

var result = combineWords('dog', 'house');
console.log(result);
// displays 'doghouse'

2. Repeat a phrase

Display an argument phrase to the console n times

function repeatPhrase(phrase, n) {
	// TODO: Place your code here
}

repeatPhrase("Hello", 5);
// displays
// Hello
// Hello
// Hello
// Hello
// Hello

3. Build your own Power function

Return number ^power without using built-in Math functions

Example:
4⁵ = 4 * 4 * 4 * 4 * 4 = 1024

function toTheNthPower(number, power) {
	// TODO: Place your code here		
}

var result = toTheNthPower(4, 5);
console.log(result);
// displays 1024

4. Area of a circle: π r²

Return the area of a circle given the radius
background information

function areaOfACircle(radius) {
	// TODO: Place your code here
}

var result = areaOfACircle(2);
console.log(result);
// displays approximately 12.57

5. Pythagorean Theorem: a² + b² = c²

Return c given a and b
background information

function pythagoreanTheorem(a, b) {
	// TODO: Place your code here
}

var result = pythagoreanTheorem(3, 4);
conosle.log(result);
// should display 5;

6. Is X Evenly Divisible by Y ?

Return a boolean value whether or not X can be divided by Y without any remainders.

Hint: Explore the world of Modulus operators!

function isXEvenlyDivisibleByY(x, y) {
	// TODO: Place your code here
}

var result = isXEvenlyDivisibleByY(99, 3);
console.log(result);
// displays true

7. Vowel Count:

Return the number of occurrences of vowels in a word. Vowels are a, e, i, o, u, and y

function countVowels(word) {
	// TODO: Place your code here
}

var result = countVowels("stealing");
console.log(result);
// displays 3

Challenge: Can you alter the code to count both upper case AND lower case?

8. Does the array contain "wdi"

Given an array, return true if it contains the string "wdi" and false if it does not contain that string.

Example:

findWdi([9,'Bart Simpson', true, 'wdi']) // returns true
findWdi(['a','b','c']) // returns false

	function findWdi(arr){
		// TODO: Place your code here
	}

9. Build an ASCII Triangle!

Display a simple triangle with asterisks

Example:
printTriangle(5)

*
**
***
****
*****

function printTriangle(length) {
	// TODO: Place your code here
}

printTriangle(3);
// displays
// *
// **
// ***

10. Stretch Challenge: Can you alter the printTriangle function to create a Pyramid?

Example: printPyramid(10);

           *
          * *
         * * *
        * * * *
       * * * * *
      * * * * * *
     * * * * * * *
    * * * * * * * *
   * * * * * * * * *
  * * * * * * * * * *

Warning: This is a surprisingly tricky interview-level exercise. Try at your own risk!

function printPyramid(length) {
	// TODO: Place your code here
}