20150617_OC之父類指針指向子類對象

//
//  Animal.h
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Animal : NSObject
{
    NSString    *_name;
    NSInteger    _age;
}

@property (copy,nonatomic)NSString *name;
@property (assign ,nonatomic)NSInteger age;

- (void)printAnimalFood;
@end

<pre name="code" class="objc">//  Animal.m
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import "Animal.h"

@implementation Animal

- (void)printAnimalFood
{
    
}

- (NSString *)description
{
    return [NSString stringWithFormat:@"name = %@,age = %li",[self name],[self age]];
}

@end

//  Cat.h
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import "Animal.h"

@interface Cat : Animal
{
    NSString *_colorOfCat;
}
@property (copy,nonatomic)NSString *colorOfCat;
@end

//  Cat.m
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import "Cat.h"

@implementation Cat
- (void)printAnimalFood
{
    NSLog(@"Cat like to eat fish");
}

- (NSString *)description
{
    return  [NSString stringWithFormat:@"name = %@,age = %li,color = %@",_name,_age,self->_colorOfCat];
}
@end

//  Dog.h
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import "Animal.h"

@interface Dog : Animal
{
    float _weight;
}
@property (assign,nonatomic)float weight;
@end

<pre name="code" class="objc">//
//  Dog.m
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import "Dog.h"

@implementation Dog

- (void)printAnimalFood
{
    NSLog(@"Dog like to eat bone");
}

- (NSString *)description
{
    return [NSString stringWithFormat:@"name = %@,age = %li,weight = %.2f",_name,_age,_weight];
}
@end

<pre name="code" class="objc">//  main.m
//  IOS150617_ObjectiveC_父類指針指向子類對象
//
//  Created by qianfeng on 15/6/17.
//  Copyright (c) 2015年 Peng Junlong. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "Cat.h"
#import "Dog.h"

//多態,父類指針指向子類對象,
void printInfo(Animal *animal)
{
    [animal printAnimalFood];
    NSLog(@"%@",animal.description);
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        Dog *dog = [[Dog alloc]init];
        dog.name = @"狗";
        dog.age  = 12;
        dog.weight = 12.34;
        [dog printAnimalFood];
        NSLog(@"%@",dog.description);
        
        //父類的對象指針指向子類的對象
        //調用的方法看具體對象的類型,先從子類查找對應方法的實現,子類沒有實現對應的方法,跳到父類查找對應的方法實現,父類沒有實現對應的方法,再繼續向上追蹤到父類的父類
        Animal *dogAnimal = dog;
        [dogAnimal printAnimalFood];
        NSLog(@"%@",dogAnimal.description);
    
        Cat *cat = [[Cat alloc] init];
        cat.name = @"貓";
        cat.age  = 10;
        cat.colorOfCat = @"白色";
        [cat printAnimalFood];
        NSLog(@"%@",[cat description]);
        
        Animal *catAnimal = cat;
        [catAnimal printAnimalFood];
        NSLog(@"%@",catAnimal.description);
        
        NSLog(@"==========多態=========");
        //多態,根據不同的對象,打印不同的結果
        printInfo(cat);
        printInfo(dog);
    }
    return 0;
}