C++专题(二)

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class Point
 6 {
 7     float x, y;
 8 
 9 public:
10     Point()
11     {
12         x = 0;
13         y = 0;
14         cout << "执行Point()构造函数" << endl;
15     }
16 
17     Point(float a, float b)
18     {
19         x = a;
20         y = b;
21         cout << "执行Point(float a, float b)构造函数" << endl;
22     }
23 
24     ~Point()
25     {
26         cout << ‘(‘ << x << ‘,‘ << y << ")执行析构函数" << endl;
27     }
28 
29     void Set(float a = 0, float b = 0)
30     {
31         x = a;
32         y = b;
33     }
34 
35     void Display()
36     {
37         cout << "点的位置是:(" << x << ‘,‘ << y << ")" << endl;
38     }
39 };

 1 #include "point.h"
 2 
 3 void main (void)
 4 {
 5     Point a, b(3, 5);
 6     a.Display();
 7     b.Display();
 8     a.Set(6, 8);
 9     b.Set(12.5, 25.37);
10     a.Display();
11     b.Display();
12 }

 1 #include "point.h"
 2 
 3 void main (void)
 4 {
 5     Point a(4,6);
 6     a.Display();
 7     {
 8         cout << "进入了子程序块\n";
 9         Point b(3,5);
10         a.Display();
11         b.Display();
12     }
13     cout << "退出了子程序块\n";
14     a.Display();
15     //b.Display(); 若加了这一句,则会显示出错
16 }

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class Point1
 6 {
 7     float x, y;
 8 
 9 public:
10     Point1();
11     Point1(float a, float b);
12     Point1(Point1 &obj);
13     ~Point1()
14     {
15         cout << ‘(‘ << x << ‘,‘ << y << ")执行析构函数" << endl;
16     }
17 
18     void Set(float a = 0, float b = 0)
19     {
20         x = a;
21         y = b;
22     }
23 
24     void Display()
25     {
26         cout << "点的位置是:(" << x << ‘,‘ << y << ")\n";
27     }
28 };
29 
30 Point1::Point1()
31 {
32     x = 0;
33     y = 0;
34     cout << "执行Point1()构造函数" << endl;
35 }
36 
37 Point1::Point1(float a, float b)
38 {
39     x = a;
40     y = b;
41     cout << "执行Point1(float a, float b)构造函数" << endl;
42 }
43 
44 Point1::Point1(Point1 &obj)
45 {
46     x = obj.x;
47     y = obj.y;
48     cout << "执行Point1(Point1 &obj)构造函数" << endl;
49 }

 1 #include "point1.h"
 2 
 3 void main (void)
 4 {
 5     Point1 a(53, 24);
 6     a.Display();
 7     Point1 b(a);
 8     b.Display();
 9     a.Set(16, 28);
10     Point1 c(a);
11     c.Display();
12     c.Set(3.14, 6.28);
13     c.Display();
14     cout << "现在a";
15     a.Display();
16     cout << "现在b";
17     b.Display();
18     cout << "现在c";
19     c.Display();
20 }

 1 #include "point1.h"
 2 
 3 void f1(Point1 x)
 4 {
 5     cout << "f1函数在运行" << endl;
 6     x.Display();
 7     cout << "f1函数结束运行" << endl;
 8 }
 9 
10 void main (void)
11 {
12     Point1 a(3, 6.5);
13     cout << "准备运行f1函数" << endl;
14     f1(a);
15     cout << "回到了主程序" << endl;
16 }

 1 #include "point1.h"
 2 
 3 void f1(Point1 &x)
 4 {
 5     cout << "f1函数在运行" << endl;
 6     x.Display();
 7     cout << "f1函数结束运行" << endl;
 8 }
 9 
10 void main (void)
11 {
12     Point1 a(3, 6.5);
13     cout << "准备运行f1函数" << endl;
14     f1(a);
15     cout << "回到了主程序" << endl;
16 }

 1 #include "point1.h"
 2 
 3 Point1 f2(void)
 4 {
 5     Point1 x(10, 20);
 6     return x;
 7 }
 8 
 9 void main (void)
10 {
11     cout << "开始执行f2函数" << endl;
12     f2();
13     cout << "f2函数运行结束" << endl;
14 }

 1 #include <iostream>
 2 
 3 using namespace std;
 4 
 5 class Location
 6 {
 7     float x, y;
 8 
 9 public:
10     Location(float a = 0, float b = 0)
11     {
12         x = a;
13         y = b;
14     }
15 
16     float getx()
17     {
18         return x;
19     }
20 
21     float gety()
22     {
23         return y;
24     }
25 
26     void print()
27     {
28         cout << "(X, Y) = (" << x << ", " << y << ")\n";
29     }
30 };

 1 #include "location.h"
 2 
 3 void main(void)
 4 {
 5     Location A(115.5, 38.75);
 6     Location *ptr;
 7     float x, y;
 8 
 9     ptr = &A;
10     x = ptr->getx();
11     y = ptr->gety();
12     cout << "X = " << x << ", Y = " << y << endl;
13     ptr->print();
14 }