In programming, as in life, you have to make decisions and act on them. Objective-C provides control statements and loops to help your program take action. You may want to repeat a set of instructions based on some condition or state, for example, or even change the program execution sequence. Here is the basic syntax for Objective-C control statements and loops.
if else
<b>if</b> (condition) {
statement(s) if the condition is true;
}
<b>else</b> {
statement(s) if the condition is not true;
}
for
<b>for</b> (counter; condition; update counter) {
statement(s) to execute while the condition is true;
}
for in
<b>for</b> (Type newVariable <b>in</b> expression ) {
<b> </b> statement(s);
}
or
Type existingVariable ;
for (existingVariable in expression) {
statement(s);
}
*Expression is an object that conforms to the NSFastEnumeration protocol.
An NSArray and NSSet enumeration is over content.
An NSDictionary enumeration is over keys.
An NSManagedObjectModel enumeration is over entities.
while
while (condition) {
statement(s) to execute while the condition is true
}
do while
do {
statement(s) to execute while the condition is true
} while (condition);
Jump statements
return ;
Stop execution and return to the calling function.
break;
Leave a loop.
continue;
Skip the rest of the loop and start the next iteration.
goto labelName; ... labelName:
An absolute jump to another point in the program (don't use it).
exit();
Terminates your program with an exit code.