方法重写3之多态

Main.m

#import <Foundation/Foundation.h>
#import "ColorPrinte.h"
#import "Blackprinter.h"
#import "ThreeDPrinter.h"
#import "Printer.h"
#import "Person.h"

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

    /*
    //使用彩色打印机打印
    Person *person = [[Person alloc] init];
//    ColorPrinte *colorPrint = [[ColorPrinte alloc] init];
    Blackprinter *blackPrint = [[Blackprinter alloc] init];
//    [person printWithColorkPrint:colorPrint];
    //使用黑白打印机打印
//    [person printWithBlackPrint:blackPrint];

    //使用3D打印机
    ThreeDPrinter *threeDPrint = [[ThreeDPrinter alloc] init];
    [person printWith3DPrint:threeDPrint];
     */

    /*

     人 *人 = ［男人 alloc］init］；

     */
    //用父类声明的变量指向子类的对象
//    Printer *printer = [[ColorPrinte alloc] init];
//    [printer print];

    //--------------------多态---------------------
    Person *person = [[Person alloc] init];
    //创建三个打印机
    ColorPrinte *colorPrint = [[ColorPrinte alloc] init];
    Blackprinter *blackPrint = [[Blackprinter alloc] init];
    ThreeDPrinter *threeDPrint = [[ThreeDPrinter alloc] init];

    int cmd;

    while (1) {
        NSLog(@"请输入选择的打印机类型（1、黑白，2、彩色，3、3D）：");
        scanf("%d",&cmd);

        if (cmd == 1) {
            [person printer:blackPrint];
        }else if (cmd == 2) {
            [person printer:colorPrint];
        }else if (cmd == 3) {
            [person printer:threeDPrint];
        }else {
            NSLog(@"输入有误");
        }
    }

    /*

     多态：
     1、继承
     2、方法重写
     3、父类声明的变量指向子类对象
     */

    return 0;

Person.h

#import <Foundation/Foundation.h>
#import "Blackprinter.h"
#import "ColorPrinte.h"
#import "ThreeDPrinter.h"
#import "Printer.h"

@interface Person : NSObject

/*
//使用黑白打印机
- (void)printWithBlackPrint:(Blackprinter *)blackPrint;
//使用彩色打印机
- (void)printWithColorkPrint:(ColorPrinte *)colorPrint;

//使用3D打印机
- (void)printWith3DPrint:(ThreeDPrinter *)threeDPrint;
*/

- (void)printer:(Printer *)printer;

Person.m

#import "Person.h"

@implementation Person

/*
//使用黑白打印机
- (void)printWithBlackPrint:(Blackprinter *)blackPrint {

    //调用黑白打印机的打印方法
    [blackPrint print];

}

//使用彩色打印机
- (void)printWithColorkPrint:(ColorPrinte *)colorPrint {

    //调用彩色打印机的打印方法
    [colorPrint print];

}

//使用3D打印机
- (void)printWith3DPrint:(ThreeDPrinter *)threeDPrint {

    [threeDPrint print];

}
 */

- (void)printer:(Printer *)printer {

    [printer print];

}

Printer.h

- (void)print;

Printer.m

- (void)print {

    NSLog(@"打印机打印纸张");

}

BlackPrinter.m

- (void)print {

    NSLog(@"黑白打印机打黑白印纸张");

}

ColorPrinter.m

- (void)print {

    NSLog(@"彩色打印机打印彩色纸张");

}

ThreeDPrinter.m

- (void)print {

    NSLog(@"3D打印机打印3D");

}