5.4 Counting

Counting up with a while loop

• The programmer can use a variable to count the number of iterations, called a loop variable

• A common error is to forget to include the loop variable update (e.g., i = i +1) at the end of the loop, causing an unintended infinite loop.

Counting down with a while loop

• The loop body executes when i is 5, 4, 3, 2, and 1, but does not execute when i reaches 0.

Shorthand operators

• Covered in 2.5/6/7
• The item on the right can be an expression, so num *= x + y is shorthand for num = num * (x + y)