重点是关于学生的狗的那块，有点不懂，怎么定义和实现的

1. #import <Foundation/Foundation.h>
   
2. 
   
3. typedef enum {
   
4.     SexMan,
   
5.     SexWoman
   
6. } Sex;
   
7. 
   
8. typedef struct {
   
9.     int year;
   
10.     int month;
    
11.     int day;
    
12. } Date;
    
13. 
    
14. 
    
15. typedef enum {
    
16.     ColorBlack,
    
17.     ColorRed,
    
18.     ColorGreen
    
19. } Color;
    
20. 
    
21. @interface Dog : NSObject
    
22. {
    
23.     @public
    
24.     double weight; // 体重
    
25.     Color curColor; // 毛色
    
26. }
    
27. 
    
28. - (void)eat;
    
29. - (void)run;
    
30. @end
    
31. 
    
32. @implementation Dog
    
33. - (void)eat
    
34. {
    
35.     // 每吃一次，体重就加1
    
36.     weight += 1;
    
37.     //weight = weight +  1;
    
38.     NSLog(@"狗吃完这次后的体重是%f", weight);
    
39. }
    
40. 
    
41. - (void)run
    
42. {
    
43.     weight -= 1;
    
44.     NSLog(@"狗跑完这次后的体重是%f", weight);
    
45. }
    
46. @end
    
47. 
    
48. /*
    
49. 学生
    
50. 成员变量：性别、生日、体重、最喜欢的颜色、狗(体重、毛色，吃、跑)
    
51. 方法：吃、跑步、遛狗(让狗跑)、喂狗（让狗吃）
    
52. */
    
53. @interface Student : NSObject
    
54. {
    
55.     @public
    
56.     Sex sex; // 性别
    
57.     Date birthday; // 生日
    
58.     double weight; // 体重(kg)
    
59.     Color favColor; // 最喜欢的颜色
    
60.     char *name;
    
61.    
    
62.     // 重点：狗
    
63.     Dog *dog;
    
64. }
    
65. - (void)eat;
    
66. - (void)run;
    
67. - (void)print;
    
68. 
    
69. - (void)liuDog;
    
70. - (void)weiDog;
    
71. @end
    
72. 
    
73. @implementation Student
    
74. 
    
75. - (void)liuDog
    
76. {
    
77.     // 让狗跑起来（调用狗的run方法）
    
78.     [dog run];
    
79. }
    
80. 
    
81. - (void)weiDog
    
82. {
    
83.     // 让狗吃东西(调用狗的eat方法)
    
84.     [dog eat];
    
85. }
    
86. 
    
87. - (void)print
    
88. {
    
89.     NSLog(@"性别=%d, 喜欢的颜色=%d, 姓名=%s, 生日=%d-%d-%d", sex, favColor, name, birthday.year, birthday.month, birthday.day);
    
90. }
    
91. 
    
92. - (void)eat
    
93. {
    
94.     // 每吃一次，体重就加1
    
95.     weight += 1;
    
96.     //weight = weight +  1;
    
97.     NSLog(@"学生吃完这次后的体重是%f", weight);
    
98. }
    
99. 
    
100. - (void)run
     
101. {
     
102.     weight -= 1;
     
103.     NSLog(@"学生跑完这次后的体重是%f", weight);
     
104. }
     
105. @end
     
106. 
     
107. int main()
     
108. {
     
109.     Student *s = [Student new];
     
110.    
     
111.     Dog *d = [Dog new];
     
112.     d->curColor = ColorGreen;
     
113.     d->weight = 20;
     
114.     s->dog = d;
     
115.    
     
116.    
     
117.     [s liuDog];
     
118.    
     
119.     [s weiDog];
     
120.     return 0;
     
121. }
     
122. 
     
123. 
     
124. void test()
     
125. {
     
126.     Student *s = [Student new];
     
127.     s->weight = 50;
     
128.    
     
129.     // 性别
     
130.     s->sex = SexMan;
     
131.    
     
132.     // 生日
     
133.     Date d = {2011, 9, 10};
     
134.     s->birthday = d;
     
135.    
     
136.     s->name = "Jack";
     
137.    
     
138.     /*
     
139.      s->birthday.year = 2011;
     
140.      s->birthday.month = 9;
     
141.      s->birthday.day = 10;
     
142.      */
     
143.    
     
144.     // 喜欢的颜色
     
145.     s->favColor = ColorBlack;
     
146.     /*
     
147.      [s eat];
     
148.      [s eat];
     
149.      
     
150.      [s run];
     
151.      [s run];
     
152.      */
     
153.    
     
154.     [s print];
     
155. }
     

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重点是关于学生的狗的那块，有点不懂，怎么定义和实现的

1. #import <Foundation/Foundation.h>
   
2. 
   
3. typedef enum {
   
4.     SexMan,
   
5.     SexWoman
   
6. } Sex;
   
7. 
   
8. typedef struct {
   
9.     int year;
   
10.     int month;
    
11.     int day;
    
12. } Date;
    
13. 
    
14. 
    
15. typedef enum {
    
16.     ColorBlack,
    
17.     ColorRed,
    
18.     ColorGreen
    
19. } Color;
    
20. 
    
21. @interface Dog : NSObject
    
22. {
    
23.     @public
    
24.     double weight; // 体重
    
25.     Color curColor; // 毛色
    
26. }
    
27. 
    
28. - (void)eat;
    
29. - (void)run;
    
30. @end
    
31. 
    
32. @implementation Dog
    
33. - (void)eat
    
34. {
    
35.     // 每吃一次，体重就加1
    
36.     weight += 1;
    
37.     //weight = weight +  1;
    
38.     NSLog(@"狗吃完这次后的体重是%f", weight);
    
39. }
    
40. 
    
41. - (void)run
    
42. {
    
43.     weight -= 1;
    
44.     NSLog(@"狗跑完这次后的体重是%f", weight);
    
45. }
    
46. @end
    
47. 
    
48. /*
    
49. 学生
    
50. 成员变量：性别、生日、体重、最喜欢的颜色、狗(体重、毛色，吃、跑)
    
51. 方法：吃、跑步、遛狗(让狗跑)、喂狗（让狗吃）
    
52. */
    
53. @interface Student : NSObject
    
54. {
    
55.     @public
    
56.     Sex sex; // 性别
    
57.     Date birthday; // 生日
    
58.     double weight; // 体重(kg)
    
59.     Color favColor; // 最喜欢的颜色
    
60.     char *name;
    
61.    
    
62.     // 重点：狗
    
63.     Dog *dog;
    
64. }
    
65. - (void)eat;
    
66. - (void)run;
    
67. - (void)print;
    
68. 
    
69. - (void)liuDog;
    
70. - (void)weiDog;
    
71. @end
    
72. 
    
73. @implementation Student
    
74. 
    
75. - (void)liuDog
    
76. {
    
77.     // 让狗跑起来（调用狗的run方法）
    
78.     [dog run];
    
79. }
    
80. 
    
81. - (void)weiDog
    
82. {
    
83.     // 让狗吃东西(调用狗的eat方法)
    
84.     [dog eat];
    
85. }
    
86. 
    
87. - (void)print
    
88. {
    
89.     NSLog(@"性别=%d, 喜欢的颜色=%d, 姓名=%s, 生日=%d-%d-%d", sex, favColor, name, birthday.year, birthday.month, birthday.day);
    
90. }
    
91. 
    
92. - (void)eat
    
93. {
    
94.     // 每吃一次，体重就加1
    
95.     weight += 1;
    
96.     //weight = weight +  1;
    
97.     NSLog(@"学生吃完这次后的体重是%f", weight);
    
98. }
    
99. 
    
100. - (void)run
     
101. {
     
102.     weight -= 1;
     
103.     NSLog(@"学生跑完这次后的体重是%f", weight);
     
104. }
     
105. @end
     
106. 
     
107. int main()
     
108. {
     
109.     Student *s = [Student new];
     
110.    
     
111.     Dog *d = [Dog new];
     
112.     d->curColor = ColorGreen;
     
113.     d->weight = 20;
     
114.     s->dog = d;
     
115.    
     
116.    
     
117.     [s liuDog];
     
118.    
     
119.     [s weiDog];
     
120.     return 0;
     
121. }
     
122. 
     
123. 
     
124. void test()
     
125. {
     
126.     Student *s = [Student new];
     
127.     s->weight = 50;
     
128.    
     
129.     // 性别
     
130.     s->sex = SexMan;
     
131.    
     
132.     // 生日
     
133.     Date d = {2011, 9, 10};
     
134.     s->birthday = d;
     
135.    
     
136.     s->name = "Jack";
     
137.    
     
138.     /*
     
139.      s->birthday.year = 2011;
     
140.      s->birthday.month = 9;
     
141.      s->birthday.day = 10;
     
142.      */
     
143.    
     
144.     // 喜欢的颜色
     
145.     s->favColor = ColorBlack;
     
146.     /*
     
147.      [s eat];
     
148.      [s eat];
     
149.      
     
150.      [s run];
     
151.      [s run];
     
152.      */
     
153.    
     
154.     [s print];
     
155. }
     

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