使用copy再次实现Circle类，保证不能有内存泄漏问题

1 #import <Foundation/Foundation.h>
2 //xieyi
3 @protocol showOn
4 @required
5 -(void)printOn;
6 @end
7 // lei
8 @interface MyPoint : NSObject<showOn,NSCopying>{
9     int x;
10     int y;
11 }
12 @property (nonatomic,assign)int x,y;
13 -(id)initWithX:(int)_x andY:(int)_y;
14 @end
15 // leibie fenlei
16 @interface MyPoint(MoveSet)
17
18 -(void)moveToX:(int)_x andY:(int)_y;
19
20
21 @end
22
23 #import "MyPoint.h"
24
25 @implementation MyPoint
26 @synthesize x,y;
27 -(id)initWithX:(int)_x andY:(int)_y{
28     if(_x==0)
29         x=1;
30     if(_y==0)
31         y=1;
32     x=_x;
33     y=_y;
34     return self;
35 }
36 -(id)copyWithZone:(NSZone *)zone{
37     MyPoint* newPoint=[[MyPoint allocWithZone:zone] initWithX:x andY:y];
38     return newPoint;
39 }
40 -(void)printOn{
41     NSLog(@" x = %d , y = %d ",x,y);
42 }
43 @end
44 @implementation MyPoint(MoveSet)
45 -(void)moveToX:(int)_x andY:(int)_y{
46     x=_x;
47     y=_y;
48 }
49 @end
50
51 #import <Foundation/Foundation.h>
52 #import "MyPoint.h"
53
54 @interface Circle : NSObject<showOn>{
55     MyPoint* point;
56     int radius;
57 }
58 @property (nonatomic,copy)MyPoint* point;
59 @property (nonatomic,assign)int radius;
60 -(id)initWithPoint:(MyPoint* )_p andRadius:(int)_r;
61 -(id)initWithPoint:(MyPoint *)_p;
62
63 @end
64
65
66 #import "Circle.h"
67
68 @implementation Circle
69 @synthesize point;
70 @synthesize radius;
71
72 -(id)initWithPoint:(MyPoint *)_p andRadius:(int)_r{
73     if(_r==0)
74     {
75         radius=1;
76     }
77     if(_p==nil)
78         return nil;
79     if(self=[super init])
80     {
81         if(point!=_p)
82         {
83             if(point)
84                 [point release];
85             point =[[MyPoint alloc]initWithX:_p.x andY:_p.y];
86         }
87
88     }
89         radius=_r;
90         return self;
91 }
92
93
94 -(id)initWithPoint:(MyPoint*)_p{
95     self=[self initWithPoint:_p andRadius:10];
96     return self;
97 }
98
99 -(void)printOn{
100     NSLog(@"point(x,y) = (%d,%d),radius = %d",point.x,point.y,radius);
101 }
102
103 -(void) dealloc{
104     [point release];
105     [super dealloc];
106 }
107
108 @end