继承的实现（代码）

//

//  main.m

//  jicheng

//

//  Created by mac on 15/12/7.

//  Copyright © 2015年 wx. All rights reserved.

//

#import <Foundation/Foundation.h>

#pragma mark Animal

@interface Animal : NSObject

-(void)eat:(NSString *)foodname;

@end

@implementation Animal

-(void)eat:(NSString *)foodname{

    NSLog(@"吃食物%@",foodname);

}

@end

#pragma mark Dog

@interface Dog : Animal

-(void)kanmen;

@end

@implementation Dog

-(void)kanmen{

    NSLog(@"wang,wang...");

}

@end

#pragma mark Cat

@interface Cat : Animal

-(void)zhualaoshu;

@end

@implementation Cat

-(void)zhualaoshu{

    NSLog(@"miao,miao...");

}

@end

int main(int argc,const char * argv[]) {

    @autoreleasepool {

       

        Animal * an1 = [Animalnew];

        [an1 eat:@"馒头"];

        

        Dog * d1 = [Dognew];

        [d1 kanmen];

        [d1 eat:@"骨头"];

        

        Cat * c1 = [Catnew];

        [c1 eat:@"老鼠"];

        [c1 zhualaoshu];

        

        

    }

    return0;

}