Why does Objective-C use YES and NO instead of 1 and 0?

Question

Is there any technical reason why Objective-C uses YES and NO instead of 1 and 0, or is it simply to make it more readable?

Answer 1

Making it more readable is a technical reason.

Answer 2

It's just syntax, there's no technical reason for it. They just use YES/NO for their BOOL instead of true/false like c++ does.

Answer 3

The same reason most languages use true and false... You can use 1 and 0 if you like, same as any of those other languages.

Really, if you think about it, we're talking about:

#define YES 1
#define NO  0

It's simply nicer to read.

Answer 4

It's the same as true/false..

Don't ask me why they reinvented the wheel and changed the names.

My pesonal guess is, that the language designer thought it would be cool to be different... (Yes, I know I will get downvotes from the fan-boys)..

Answer 5

C (on which Objective-C is based) didn't have a boolean type until C99.

Objective-C was created in the 80s and defined it's own boolean type.

Answer 6

typedef signed char        BOOL; 
// BOOL is explicitly signed so @encode(BOOL) == "c" rather than "C" 
// even if -funsigned-char is used.
#define OBJC_BOOL_DEFINED


#define YES             (BOOL)1
#define NO              (BOOL)0

(For reference)

[button setAttr:YES];

Sounds nicer IMHO then...

[button setAttr:TRUE];

Answer 7

Because the programmer means yes and no, not 1 and 0.