IntroductionToFunction.md

Introduction to Functions Instructor Notes

Objectives

• Explain the purpose and function of a Function
• Write Functions
• Write Functions with 0, 1, and 2+ parameters
• Invoke Functions as Expressions

Explain the purpose and function of a Function

Turn to your neighbor and explain why functions are useful. Be prepared to share your answer with the class.

Write Functions

On your desks, write a function that prints out the numbers 0 - 9.

Write Functions with 0, 1, and 2+ parameters

On your desks, write a function named printIfDivisible that takes two parameters:

• Name first parameters countUpTo.
• Name second parameter divisor.

Your function should loop from 0 to and include countUpTo, and only prints out numbers in the count if they are evenly divisible by divisor

Example:

printIfDivisible(10,2) // 0, 2, 4, 6, 8, 10

printIfDivisible(10,3) // 0, 3, 6, 9

printIfDivisible(20,5) // 0, 5, 10, 15, 20

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On your desks, write a function named sumAll that will take 0 or more arguments, and return the sum of all arguments.

Example:

sumAll() // 0

sumAll(10) // 10

sumAll(1,2,3,4,5,6) // 21

Invoke Functions as Expressions

The following equation is an equation that gets the length of a hypotenuse of a right angle, where a and b and the lenghts of the sides at a right angle.

c = sqrt(a^2 + b^2)

Using the following functions:

• Math.pow()
• Math.sqrt()

And the following variables:

var a = 3;
var b = 4;

Write an expression that creates a variable named c and assign the value of the length of the hypotenuse of a right angle with sides if length a and b