为学IOS,进击中...之OC多态练习

打印机,实现多态.输入1,使用彩色打印机.输入2,使用黑白打印机

(一)main函数:

#import <Foundation/Foundation.h>

#import "Person.h"

#import "Printer.h"

#import "BlackPrinter.h"

#import "ColorPrinter.h"

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

Person *person = [[Person alloc] init];

Printer *printer1 = [[BlackPrinter alloc] init];

Printer *printer2 = [[ColorPrinter alloc] init];

NSInteger a;

NSLog(@"输入1和2调换打印机");

scanf("%ld",&a);

if (a == 1) {

[person print:printer1];

}

else

[person print:printer2];

return 0;

}

(二)Printer类

#import <Foundation/Foundation.h>

@interface Printer : NSObject

- (void)doPrint;

@end

#import "Printer.h"

@implementation Printer

- (void)doPrint{

NSLog(@"打印机实现了打印");

}

@end

(三)Person类

#import <Foundation/Foundation.h>

#import "Printer.h"

@interface Person : NSObject

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

@end

#import "Person.h"

@implementation Person

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

[printer doPrint];

}

@end

(四)ColorPrinter类

#import "Printer.h"

@interface ColorPrinter : Printer

@end

#import "ColorPrinter.h"

@implementation ColorPrinter

- (void)doPrint{

NSLog(@"彩色打印机实现了打印");

}

@end

(五)BlackPrinter与ColorPrinter类相似,此处省略.

到此,就解决了这个简单的多态问题