Page 59

Swift The key point of a while loop is that the loop might not ever run. When the condition is tested and the result is false, the loop body will be skipped and the first statement after the while loop will be executed.

Example import Cocoa

var index = 10

while index < 20 { println( "Value of index is \(index)") index = index + 1 } Here we are using comparison operator < to compare the value of the variable index against 20. While the value of index is less than 20, the while loop continues executing a block of code next to it and as soon as the value of index becomes equal to 20, it comes out. When executed, the above code produces the following result: Value of index is 10 Value of index is 11 Value of index is 12 Value of index is 13 Value of index is 14 Value of index is 15 Value of index is 16 Value of index is 17 Value of index is 18 Value of index is 19

Swift â&#x20AC;&#x201C; do-while Loop Unlike for and while loops, which test the loop condition at the top of the loop, the do...while loop checks its condition at the bottom of the loop. A do...while loop is similar to a while loop, except that a do...while loop is guaranteed to execute at least once.


​Quick is a strong and intuitive development language for macOS, iOS, watchOS and tvOS....