while loops

Swift provides while and repeat-while loops. A while or repeat-while loop performs a set of expressions until a condition becomes false. Consider the following example:

var n = 2 
while n < 100 { 
    n = n * 2 
} 
var m = 2 
repeat { 
    m = m * 2 
} while m < 100 

The while loop evaluates its condition at the beginning of each iteration. The repeat-while loop evaluates its condition at the end of each iteration.