freecodecamp--freecodecamp/curriculum/challenges/english/blocks/basic-javascript/56533eb9ac21ba0edf2244aa.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
56533eb9ac21ba0edf2244aa	Understanding Uninitialized Variables	1	18335	understanding-uninitialized-variables

--description--

When JavaScript variables are declared, they have an initial value of undefined. If you do a mathematical operation on an undefined variable your result will be NaN which means "Not a Number". If you concatenate a string with an undefined variable, you will get a string of undefined.

--instructions--

Initialize the three variables a, b, and c with 5, 10, and "I am a" respectively so that they will not be undefined.

--hints--

a should be defined and have a final value of 6.

assert(typeof a === 'number' && a === 6);

b should be defined and have a final value of 15.

assert(typeof b === 'number' && b === 15);

c should not contain undefined and should have a final value of the string I am a String!

assert(!/undefined/.test(c) && c === 'I am a String!');

You should not change code below the specified comment.

assert(
  /a = a \+ 1;/.test(__helpers.removeJSComments(code)) &&
    /b = b \+ 5;/.test(__helpers.removeJSComments(code)) &&
    /c = c \+ " String!";/.test(__helpers.removeJSComments(code))
);

--seed--

--seed-contents--

// Only change code below this line
var a;
var b;
var c;
// Only change code above this line

a = a + 1;
b = b + 5;
c = c + " String!";

--solutions--

var a = 5;
var b = 10;
var c = "I am a";
a = a + 1;
b = b + 5;
c = c + " String!";