Static variable of Object-C)

"+" Of Object-C is similar to static functions in C ++. It can access variables declared by static. Example:

1. Code:

// Classa. h

# Import <Foundation/nsobject. h>

Static int count;

@ Interface classa: nsobject

+ (INT) initcount;
+ (Void) initialize;
@ End

/// Classa. m

# Import "classa. H"

@ Implementation classa
-(ID) Init {
Self = [Super init];
Count ++;
Return self;
}

+ (INT) initcount {
Return count;
}

+ (Void) initialize {
Count = 0;
}
@ End

// Main. m

# Import "classa. H"
# Import <stdio. h>

Int main (INT argc, const char * argv []) {
Classa * C1 = [[classa alloc] init];
Classa * C2 = [[classa alloc] init];

// Print count
Printf ("classa count: % I \ n", [classa initcount]);

Classa * C3 = [[classa alloc] init];

// Print count again
Printf ("classa count: % I \ n", [classa initcount]);

[C1 release];
[C2 release];
[C3 release];

Return 0;
}

Running result:

Classa count: 2
Classa count: 3

2. Description:

(1) initialize is automatically called and called only once;

(2) initcount can access count.