[問題] self用法
code
@implementation Dog
- (NSString*) bark {
return @"Woof!";
}
- (NSString*) speak {
return [self bark];
}
@end
@implementation Basenji : Dog
- (NSString*) bark {
return @"";
}
@end
Basenji* b = [Basenji new];
NSString* s = [b speak];
1.這樣是呼叫Basenji class的bark method ,還是呼叫Dog class的bark method
2.為什麼我編譯後是出現Program ended with exit code: 0
而不是字串？
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Dog.h
#import <Foundation/Foundation.h>
@interface Dog : NSObject
- (NSString*) bark ;
- (NSString*) speak ;
@end
Dog.m
#import "Dog.h"
@implementation Dog
- (NSString*) bark {
return @"Woof!";
}
- (NSString*) speak {
return [self bark];
}
@end
Basenji.h
#import "Dog.h"
@interface Basenji : Dog
- (NSString*) bark;
@end
Basenji.m
#import "Basenji.h"
@implementation Basenji
- (NSString*) bark {
return @"123"; // empty string, Basenjis can't bark
};
@end
main.m
#import <Foundation/Foundation.h>
#import "Dog.h"
#import "Basenji.h"
int main(int argc, const char * argv[]) {
@autoreleasepool {
Basenji* b = [Basenji new];
NSString* s = [b speak];
NSLog(@" %@ .",s);//修改後
}
return 0;
}
※ 編輯: angelina877 (118.171.68.185), 11/03/2015 22:00:44
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[b speak]->[b bark]
這句話看不懂
沒有就會得到Woof，有就會得到123
這句話的意思是
如果我在Basenji class 沒有bark method得到Woof
如果我在Basenji class 有寫bark method得到123
理解對嗎？
※ 編輯: angelina877 (118.171.68.185), 11/03/2015 22:29:51
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※ 編輯: angelina877 (118.171.68.185), 11/03/2015 22:41:38
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