Objective-C:继承的体现

典型的继承例子：形状Shape为基类，继承它的类有:点类Point、圆类Circle、球体类Sphere、矩形类Rectangle、正方形类Square

　　　　　　　　点类Point也为基类，继承它的类有：圆类Circle、球体类Sphere、矩形类Rectangle、正方形类Square

　　　　　　　　圆类Circle也为基类，继承它的类有：球体类Sphere

　　　　　　　　矩形类Rectangle为基类，继承它的类是：正方形类Square　

//Shape类   .h和.m文件

 //  Shape.h
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  形状类

 #import <Foundation/Foundation.h>

 @interface Shape : NSObject
 @property(nonatomic,assign)CGFloat length;
 @property(nonatomic,assign)CGFloat area;
 @property(nonatomic,assign)CGFloat volum;
 -(void)draw;
 -(void) Area;
 -(void) Length;
 -(void) Volum;
 @end

 //  Shape.m
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  形状类

 #import "Shape.h"

 @implementation Shape
 -(void)draw
 {
     NSLog(@"drawing a Shape!");
 }
 -(void) Area{}
 -(void) Length{}
 -(void) Volum{}
 @end

//Point类 .h和.m文件

 //  Point.h
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  点类

 #import "Shape.h"

 @interface MyPoint : Shape
 @property(nonatomic,assign) CGFloat x;
 @property(nonatomic,assign) CGFloat y;
 -(id)initWithX:(CGFloat)m andY:(CGFloat)n;
 -(void)show;
 @end

 //  Point.m
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  点类

 #import "MyPoint.h"

 @implementation MyPoint
 -(id)initWithX:(CGFloat)m andY:(CGFloat)n
 {
     self = [super init];
     if(self)
     {
         _x = m;
         _y = n;
     }
     return self;
 }
 -(void)draw
 {
     NSLog(@"drawing a point!");
 }
 -(void)show
 {
     NSLog(@"x:%.1f,y:%.1f",_x,_y);
 }
 @end

//圆类Circle   .h和.m文件

 //  Circle.h
 //  继承
 //
 //  Created by ma c on 15/8/12.
 //  Copyright (c) 2015年. All rights reserved.
 //  圆类

 #import "MyPoint.h"

 @interface Circle : MyPoint
 @property(nonatomic,assign)CGFloat radius;
 -(id)initWithX:(CGFloat)m andY:(CGFloat)n andRadius:(CGFloat)r;
 @end

 //  Circle.m
 //  继承
 //
 //  Created by ma c on 15/8/12.
 //  Copyright (c) 2015年. All rights reserved.
 //  圆类

 #import "Circle.h"
 #define PI 3.14
 @implementation Circle
 -(id)initWithX:(CGFloat)m andY:(CGFloat)n andRadius:(CGFloat)r
 {
     self = [super init];
     if(self)
     {
         super.x = m;
         super.y = n;
         _radius = r;
     }
     return self;
 }
 -(void) Area
 {
     super.area = PI*_radius*_radius;
 }
 -(void) Length
 {
     super.length = *PI*_radius;
 }
 -(void)draw
 {
     NSLog(@"drawing a circle!");
 }
 -(void)show
 {
     [super show];
     NSLog(@"radius:%.1f,area:%.1f,Length:%.1f",_radius,super.area,super.length);
 }
 @end

//球体类Sphere   .h和.m文件

 //  Sphere.h
 //  继承
 //
 //  Created by ma c on 15/8/12.
 //  Copyright (c) 2015年. All rights reserved.
 //  球体类

 #import "Circle.h"

 @interface Sphere : Circle
 @property(nonatomic,assign)CGFloat z;
 -(id)initWithX:(CGFloat)m andY:(CGFloat)n andZ:(CGFloat)t andRadius:(CGFloat)r;
 @end

 //  Sphere.m
 //  继承
 //
 //  Created by ma c on 15/8/12.
 //  Copyright (c) 2015年. All rights reserved.
 //  球体类

 #import "Sphere.h"
 #define PI 3.14
 @implementation Sphere
 @synthesize z;
 -(id)initWithX:(CGFloat)m andY:(CGFloat)n andZ:(CGFloat)t andRadius:(CGFloat)r
 {
     if(self = [super init])
     {
         super.x = m;
         super.y = n;
         z = t;
         super.radius = r;
     }
     return self;
 }
 -(void)draw
 {
     NSLog(@"draw a sphere!");
 }
 -(void) Area
 {
     super.area = *PI*super.radius*super.radius;
 }
 -(void) Volum
 {
     super.volum = /*PI*super.radius*super.radius*super.radius;
 }
 -(void)show
 {
     NSLog(@"x:%.1f,y:%.1f,z:%.1f",super.x,super.y,z);
     NSLog(@"radius:%.1f,area:%.1f,volum:%.1f",super.radius,super.area,super.volum);
 }
 @end

//矩形类Rectangle  .h和.m文件

 //  Rectangle.h
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  矩形类

 #import "MyPoint.h"

 @interface Rectangle : MyPoint

 @property(nonatomic,assign) CGFloat len;
 @property(nonatomic,assign) CGFloat hei;
 -(id)initWith:(CGFloat)m andY:(CGFloat)n andLen:(CGFloat) l andHei:(CGFloat)h;
 @end

 //  Rectangle.m
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  矩形类

 #import "Rectangle.h"

 @implementation Rectangle
 -(id)initWith:(CGFloat)m andY:(CGFloat)n andLen:(CGFloat) l andHei:(CGFloat)h
 {
     self = [super init];
     if(self)
     {
         self.x = m;
         self.y = n;
         _len = l;
         _hei = h;
     }
     return self;
 }
 -(void) Area
 {
    super.area = _len*_hei;
 }
 -(void) Length
 {
    super.length = *(_len+_hei);
 }
 -(void)draw
 {
     NSLog(@"drawing a Rectangle!");
 }
 -(void)show
 {
     [super show];
     NSLog(@"len:%.1f,hei:%.1f,area:%.1f,length:%.1f",_len,_hei,super.area,super.length);
 }
 @end

//正方形类Square .h和.m文件

 //  Square.h
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  正方形类

 #import "Rectangle.h"

 @interface Square : Rectangle
 @end

 //  Square.m
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //  正方形类

 #import "Square.h"

 @implementation Square
 -(void) Area
 {
     self.area = super.len*super.hei;
 }
 -(void) Length
 {
     self.length = *self.len;
 }
 -(void)draw
 {
     NSLog(@"drawing a Square!");
 }
 -(void)show
 {
     [super show];
 }
 @end

//主函数测试

 //  main.m
 //  继承
 //
 //  Created by ma c on 15/8/11.
 //  Copyright (c) 2015年. All rights reserved.
 //

 #import <Foundation/Foundation.h>
 #import "Shape.h"
 #import "Square.h"
 #import "MyPoint.h"
 #import "Rectangle.h"
 #import "Circle.h"
 #import "Sphere.h"
 int main(int argc, const char * argv[])
 {
     @autoreleasepool
     {
         Shape *shape = [[Shape alloc]init];
         [shape draw];
         printf("\n");

         MyPoint *mypoint = [[MyPoint alloc]initWithX:0.0 andY:0.0];
         [mypoint draw];
         [mypoint show];
         printf("\n");

         Circle *circle = [[Circle alloc]initWithX:1.1 andY:1.1
                                         andRadius:5.0];
         [circle Area];
         [circle Length];
         [circle draw];
         [circle show];
         printf("\n");

         Rectangle *rectangle = [[Rectangle alloc]initWith:2.2 andY:2.2 andLen: andHei:];
         [rectangle Area];
         [rectangle Length];
         [rectangle draw];
         [rectangle show];
         printf("\n");

         Square *square = [[Square alloc]initWith:3.3 andY:3.3 andLen: andHei:];
         [square Area];
         [square Length];
         [square draw];
         [square show];
         printf("\n");

         Sphere *sphere = [[Sphere alloc]initWithX:4.4 andY:4.4 andZ:4.4 andRadius:6.0];
         [sphere Area];
         [sphere Volum];
         [sphere draw];
         [sphere show];
         printf("\n");
     }
     return ;
 }

//运行结果

-- ::15.931 继承[:] drawing a Shape!

-- ::15.933 继承[:] drawing a point!
-- ::15.933 继承[:] x:0.0,y:0.0

-- ::15.933 继承[:] drawing a circle!
-- ::15.933 继承[:] x:1.1,y:1.1
-- ::15.933 继承[:] radius:5.0,area:78.5,Length:31.4

-- ::15.934 继承[:] drawing a Rectangle!
-- ::15.934 继承[:] x:2.2,y:2.2
-- ::15.934 继承[:] len:3.0,hei:8.0,area:24.0,length:22.0

-- ::15.934 继承[:] drawing a Square!
-- ::15.934 继承[:] x:3.3,y:3.3
-- ::15.934 继承[:] len:4.0,hei:4.0,area:16.0,length:16.0

-- ::15.935 继承[:] draw a sphere!
-- ::15.935 继承[:] x:4.4,y:4.4,z:4.4
-- ::15.935 继承[:] radius:6.0,area:452.2,volum:678.2

Program ended with exit code: 

注释：继承Shape的形状基本都具有自己的坐标及其对应的属性(如半径、长、高、宽、面积、周长、体积等)。当然，视情况去定义。