matthewvilhauer / functions-exercises

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

Exercises - Javascript Functions

Fork this repository to your GitHub account, then clone your GitHub copy onto your computer.

You'll be filling in a bunch of empty function definitions. Type each function definition into the snippet, then add the rest of the code to make the function work.

After you implement a function successfully in your snippet, copy it over into the functions.js file. Unless a different behavior is specified, have the function log the answer to the console AND return it.

When class ends, push your work to GitHub and open a pull request to the class functions-exercises repo!

For some of the problems, you'll have to use functions or other variables supplied by JavaScript's built-in Math object. Here is the documentation on using the Math object.

Example Usage of Math

	var absoluteValue = Math.abs(-4);
	// evaluates to 4
	
	var fourSquared = Math.pow(4, 2);
	// evaluates to 16
	
	var roundedToNearestInteger = Math.round(1.22343);
	// evaluates to 1

Function Definitions!

1. Build your own concatentation

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
}

combineWords('dog', 'house');
// 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		
}

toTheNthPower(4, 5);
// 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
}

areaOfACircle(2);
// 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
}

pythagoreanTheorem(3, 4);
// 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
}

isXEvenlyDivisibleByY(99, 3);
// displays true

7. Vowel Count:

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

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

countVowels("stealing");
// displays 3

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

8. Build an ASCII Triangle!

Display a simple triangle with asterisks

Example:
printTriangle(5)

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

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

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

9. 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
}