day06-05-多态-偷吃

Objective-c

//  main.m
//  偷吃
//
//  Created by Aaron on 15/7/8.
//  Copyright (c) 2015年 Aaron. All rights reserved.
//
#import <Foundation/Foundation.h>
//2.幼儿园老师问,谁偷吃了苹果?
//孩子类回答说不知道
//女孩类回答 是他偷吃了
//男孩类回答 不是我
#import "Teacher.h"
#import "Boy.h"
#import "Girl.h"
#import "Child.h"
int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Teacher *t = [[Teacher alloc] init];
        Boy *b = [[Boy alloc] init];
//        [t askToBoy:b];
        Girl *g = [[Girl alloc] init];
        [t askToChild:g];
    }
    return 0;
}
//继承的作用2: 统一接口(不是最常用的)
//继承的作用3: 当我们觉得官方的类或者第三方的类库不太适用的时候,我们可以继承这些类,然后添加自己的属性和方法
//OC是单继承
//类簇不能继承

#import <Foundation/Foundation.h>
@interface Child : NSObject
-(void)answerToTeacher;
@end

#import "Child.h"
@implementation Child
-(void)answerToTeacher
{
    NSLog(@"不知道");
}
@end

#import "Child.h"
@interface Girl : Child
@end

#import "Girl.h"
@implementation Girl
-(void)answerToTeacher
{
    NSLog(@"是他吃的");
}
@end

#import <Foundation/Foundation.h>
#import "Child.h"
@interface Teacher : NSObject
//-(void)askToBoy:(Boy *)b;
-(void)askToChild:(Child *)c;
@end

#import "Teacher.h"
@implementation Teacher
//-(void)askToBoy:(Boy *)b
//{
//    NSLog(@"谁偷吃了苹果?");
//    [b boyAnswer];
//}
-(void)askToChild:(Child *)c
{
    NSLog(@"谁偷吃了苹果?");
    [c answerToTeacher];
}
@end

#import "Child.h"
@interface Boy : Child
//-(void)boyAnswer;
@end

#import "Boy.h"
@implementation Boy
//-(void)boyAnswer
//{
//    NSLog(@"不是我");
//}
-(void)answerToTeacher
{
    NSLog(@"不是我");
}
@end