While loops

For loops are great when you know how many times you intend to loop, but if you want to loop until a certain condition is met, you need a while loop.

A while loop has the following syntax:

while <#boolean expression#> { 
    <#code to execute#> 
} 

The code block will execute over and over until the Boolean expression returns false. Therefore, it's a common pattern to change the current state in the code block that may cause the Boolean expression to change to false.

If there is no chance that the Boolean expression can become true, the code will loop forever, which can lock up your app.

Getting ready

Let's work out how many times in a row we can flip a coin and get heads.

To flip our coin,...