一、
代码：
1 #include<stdio.h>
2 #include<string.h>
3 #include<algorithm>
4 #include<iostream>
5 using namespace std;
6 class A
7 {
8 public:
9 int a,b;
10 A();
11 A(int x,int y);
12 ~A();
13 };
14 A::A()
15 {
16 printf("调用A类构造函数\n");
17 }
18 A::A(int x,int y)
19 {
20 a=x;
21 b=y;
22 printf("调用A类构造函数\n");
23 }
24 A::~A()
25 {
26 printf("调用A类析构函数\n");
27 }
28 class B:public A
29 {
30 public:
31 int aa,bb;
32 B()
33 {
34 printf("调用B类构造函数\n");
35 }
36 B(int x,int y)
37 {
38 aa=x;
39 bb=y;
40 printf("调用B类构造函数\n");
41 }
42 ~B()
43 {
44 printf("调用B类析构函数\n");
45 }
46 };
47 class C:public B
48 {
49 public:
50 int aaa,bbb;
51 B one;
52 C(int x,int y)
53 {
54 aaa=x;
55 bbb=y;
56 one.aa=x;
57 one.bb=y;
58 printf("调用C类构造函数\n");
59 }
60 ~C()
61 {
62 printf("调用C类析构函数\n");
63 }
64 };
65 int main()
66 {
67 C first(0,0);
68 printf("%d %d %d %d\n",first.aaa,first.bbb,first.one.aa,first.one.bb);
69 return 0;
70 }
二、
1 #include<stdio.h>
2 #include<string.h>
3 #include<algorithm>
4 #include<iostream>
5 using namespace std;
6 class Base
7 {
8 public:
9 Base(int x,int y)
10 {
11 a=x;
12 b=y;
13 }
14 virtual void show() //声明了虚函数，那么指针指向哪个对象就用那个对象的函数
15 { //否则的话，声明指针是什么类型就会用那个类型的函数
16 cout<<"基类内容show打印"<<endl;
17 cout<<"a:"<<a<<"b:"<<b<<endl;
18 }
19 void prinf()
20 {
21 cout<<"基类内容prinf打印"<<endl;
22 cout<<"a:"<<a<<"b:"<<b<<endl;
23 }
24 private:
25 int a,b;
26
27 };
28 class One:public Base
29 {
30 public:
31
32 One(int x,int y):Base(x,y)
33 {
34 aa=x;
35 bb=y;
36 }
37 void show()
38 {
39 cout<<"派生类内容show打印"<<endl;
40 cout<<"aa:"<<aa<<"bb:"<<bb<<endl;
41 }
42 void prinf()
43 {
44 cout<<"派生类内容prinf打印"<<endl;
45 cout<<"aa:"<<aa<<"bb:"<<bb<<endl;
46 }
47 private:
48 int aa,bb;
49 };
50 int main()
51 {
52 Base mb(100,200),*pc;
53 One mc(200,300);
54 pc=&mc;
55 pc->show();
56 pc->prinf();
57 pc=&mb;
58 pc->show();
59 pc->prinf();
60 return 0;
61 }
62
63 //2、
64 #include<stdio.h>
65 #include<string.h>
66 #include<algorithm>
67 #include<iostream>
68 using namespace std;
69 class Shape //抽象类定义是只要里面有一个纯虚函数那他就是抽象类，
70 { //抽象类不需要什么关键字来定义，且它的派生类必须覆盖重写他的纯虚方法
71 public :
72 double a;
73 Shape(double x)
74 {
75 a=x;
76 }
77 virtual void area()=0;
78 virtual void show()=0;
79 };
80 class Circle:public Shape
81 {
82 public:
83 Circle(double x):Shape(x)
84 {
85
86 }
87 void area()
88 {
89 cout<<"the circle area is :"<<endl;
90 cout<<3.14*a*a<<endl;
91 }
92 void show()
93 {
94 cout<<"a:"<<a<<endl;
95 }
96 };
97 int main()
98 {
99 Shape *ptr;
100 Circle r(6);
101 ptr=&r;
102 ptr->area();
103 ptr->show();
104 return 0;
105 }
106
107 //3、
108 #include<stdio.h>
109 #include<string.h>
110 #include<algorithm>
111 #include<iostream>
112 #include<typeinfo>
113 using namespace std;
114 class Sqare
115 {
116 public :
117 double a;
118 Sqare(double x)
119 {
120 a=x;
121 }
122 };
123 class Circle
124 {
125 public :
126 double a;
127 Circle(double x)
128 {
129 a=x;
130 }
131 };
132 int main()
133 {
134 Sqare one(1);
135 Circle two(2);
136 if(typeid(one)==typeid(Sqare)) //判断对象类型
137 {
138 cout<<"它是Sqare对象"<<endl;
139 }
140 else
141 {
142 cout<<"它是Circle对象"<<endl;
143 }
144
145 if(typeid(two)==typeid(Sqare))
146 {
147 cout<<"它是Sqare对象"<<endl;
148 }
149 else
150 {
151 cout<<"它是Circle对象"<<endl;
152 }
153 return 0;
154 }