3D Game Programming

Code in ICE, Check in the Console

The code in the rest of this chapter is too large for the JavaScript

console, so add it in ICE after the START CODING line. Be sure to keep

the JavaScript console open—even though we’re not typing code

in there, we’ll still use it to show messages.

While

If a section of code, which we call a block, starts with while, then the block is

run again and again until something changes. The something that needs to

change goes in parentheses after the while keyword:

vari = 0;

while(i < 5) {

console.log("i is now: "+ i);

i = i + 1;

}

If you try this and check in the JavaScript console, you’ll see something like

the following:

i is now: 0

i is now: 1

i is now: 2

i is now: 3

i is now: 4

Each time through the code block, we log the variable i to the JavaScript

console. We also do a little math. We add 1 to the old value of i. Then the

computer will run the while block again—as long as i is less than 5 (that <

symbol means less than). As soon as i is equal to 5 , the computer stops

rerunning the while block and moves on to the next lines.

Try This Yourself

What happens if you run the following?

vari = 0;

while(i < 5) {

console.log("Chris is awesome!!!!");

i = i + 1;

}

Be sure to try your own name!

report erratum • discuss

Repeating and Skipping Code with while and if • 75

Prepared exclusively for Michael Powell