while statement further extends the Objective-C language’s repertoire of looping capabilities. The syntax of this frequently used construct is as follows:
while ( expression ) program statement
The expression specified inside the parentheses is evaluated. If the result of the expression evaluation is
true, the program statement that immediately follows is executed. After execution of this statement (or statements, if enclosed in braces), expression is again evaluated. If the result of the evaluation is
true, the program statement is again executed. This process continues until expression finally evaluates
false, at which point the loop is terminated. Execution of the program then continues with the statement that follows ...