freecodecamp--freecodecamp/curriculum/challenges/english/blocks/basic-javascript/598e8944f009e646fc236146.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
598e8944f009e646fc236146	Understanding Undefined Value returned from a Function	1	301177	understanding-undefined-value-returned-from-a-function

--description--

A function can include the return statement but it does not have to. In the case that the function doesn't have a return statement, when you call it, the function processes the inner code but the returned value is undefined.

Example

let sum = 0;

function addSum(num) {
  sum = sum + num;
}

addSum(3);

addSum is a function without a return statement. The function will change the global sum variable but the returned value of the function is undefined.

--instructions--

Create a function addFive without any arguments. This function adds 5 to the sum variable, but its returned value is undefined.

--hints--

addFive should be a function.

assert(typeof addFive === 'function');

Once both functions have run, the sum should be equal to 8.

assert(sum === 8);

Returned value from addFive should be undefined.

assert(addFive() === undefined);

Inside the addFive function, you should add 5 to the sum variable.

assert(
  __helpers.removeWhiteSpace(addFive.toString()).match(/sum=sum\+5|sum\+=5/)
);

--seed--

--seed-contents--

// Setup
let sum = 0;

function addThree() {
  sum = sum + 3;
}

// Only change code below this line


// Only change code above this line

addThree();
addFive();

--solutions--

let sum = 0;

function addThree() {
  sum = sum + 3;
}

function addFive() {
  sum = sum + 5;
}

addThree();
addFive();