objective-cbooleanobjective-c-literals

What is the difference between @YES/@NO and YES/NO?

In Objective-c what is the difference between @YES/@NO and YES/NO? What types are used for each?

Solution

  • @YES is a short form of [NSNumber numberWithBool:YES]

    &

    @NO is a short form of [NSNumber numberWithBool:NO]

    and if we write 

    if(@NO)
   some statement;

    the above if statement will execute since the above statement will be 

    if([NSNumber numberWithBool:NO] != nil)

    and it's not equal to nil so it will be true and thus will pass.

    Whereas YES and NO are simply BOOL's and they are defined as-

    #define YES             (BOOL)1

#define NO              (BOOL)0

    YES & NO is same as true & false, 1 & 0 respectively and you can use 1 & 0 instead of YES & NO, but as far as readability is concerned YES & NO will(should) be definitely preferred.