[Objective C] 09 Posing

Posing
자세 잡기. 상속 관계에 있는 클래스 중에서 하위 클래스에게 상위 클래스에 대한 메시지에 응답하라고 설정하는 것.

Fraction.h

#import <Foundation/NSObject.h> @interface Fraction: NSObject {     int numerator;     int denominator; } -(Fraction*) initWithNumerator: (int) n andDenominator: (int) d; -(Fraction*) initWithNumerator: (int) n denominator: (int) d; -(void) print; -(void) setNumerator: (int) n; -(void) setNumerator: (int) n andDenominator: (int) d; -(void) setDenominator: (int) d; -(int) numerator; -(int) denominator; @end

Fraction.m

#import "Fraction.h" #import <stdio.h> @implementation Fraction -(Fraction*) initWithNumerator: (int) n andDenominator: (int) d {     self = [super init];         if(self) {         [self setNumerator: n andDenominator: d];     }         return self; } -(Fraction*) initWithNumerator: (int) n denominator: (int) d {     self = [super init];         if(self) {         [self setNumerator: n andDenominator: d];     }         return self; } -(void) print {     printf( "%i/%i", numerator, denominator ); } -(void) setNumerator: (int) n {     numerator = n; } -(void) setNumerator: (int) n andDenominator: (int) d {     numerator = n;     denominator = d; } -(void) setDenominator: (int) d {     denominator = d; } -(int) denominator {     return denominator; } -(int) numerator {     return numerator; } @end

FractionB.h

#import "Fraction.h" @interface FractionB: Fraction -(void) print; @end

FractionB.m

#import "FractionB.h" #import <stdio.h> @implementation FractionB -(void) print {     printf( "(%i/%i)", numerator, denominator ); } @end

main.m

#import <stdio.h> #import "Fraction.h" #import "FractionB.h" int main( int argc, const char *argv[] ) {     Fraction *frac = [[Fraction alloc] initWithNumerator: 3 denominator: 10];     // print it     printf( "The fraction is: " );     [frac print];     printf( "\n" );     // make FractionB pose as Fraction     [FractionB poseAsClass: [Fraction class]];     Fraction *frac2 = [[Fraction alloc] initWithNumerator: 3 denominator: 10];     // print it     printf( "The fraction is: " );     [frac2 print];     printf( "\n" );     // free memory     [frac release];     [frac2 release];     system("PAUSE");     return 0; }

결과

The fraction is: 3/10 The fraction is: (3/10) 계속하려면 아무 키나 누르십시오 . . .

- The method poseAsClass is part of NSObject. This allows a subclass to pose as a superclass.