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

objective-c boolean objective-c-literals
cdub picture cdub · Jun 3, 2015 · Viewed 8.5k times · Source

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

Answer

Sanjay Mohnani picture Sanjay Mohnani · Jun 3, 2015

@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.

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