实验3—初识类

 1 #include <iostream>
 2 using namespace std;
 3 class point
 4 {
 5     public:
 6         point();
 7         point(double x0,double y0);
 8         ~point();
 9         double getm()
10         {
11            return x*y;
12         }
13     private:
14         double x;
15         double y;
16 };
17 point::point(){}
18 point::point(double x0,double y0):x(x0),y(y0)         {cout<<"矩形面积为:  "<<endl;}
19 point::~point(){}
20 int main()
21 {
22     double jlong,jshort;
23     cout<<"请输入矩形的长和宽  "<<endl;
24     cin>>jlong>>jshort;
25     point p1(jlong,jshort);
26     cout << p1.getm() << endl;
27     return 0;
28 }

 1 #include <iostream>
 2 using namespace std;
 3 class Complex
 4 {
 5     public:
 6         Complex();
 7         Complex(double r0,double i0);
 8         Complex(double r0);
 9         ~Complex();
10         void add(Complex &c)// 因为c2是Complex类，所以需要用Complex定义一个参数，不过是否用引用类型无关紧要
11         {
12             real+=c.real;
13             imaginary+=c.imaginary;
14         }
15         void show()
16         {
17             cout<<real<<(imaginary>0?‘+‘:‘-‘)<<imaginary<<"i"<<endl;
18         }
19     private:
20         double real;
21         double imaginary;
22 };
23 Complex::Complex(){};//默认构造函数和析构函数在这个程序中并不是必需的（虽然编译时会自动添加缺省函数），但活用它们会起到意想不到的效果
24 Complex::Complex(double r0,double i0):real(r0),imaginary(i0){}
25 Complex::Complex(double r0):real(r0),imaginary(0){}//这里我认识到，形式不同仅仅表示不同的赋值方式，不需要因此取出变量单独赋值（实际上这也难以实现）
26 Complex::~Complex(){}
27 int main()
28 {
29     Complex c1(3,5);
30     Complex c2=4.5;
31     c2.add(c1);
32     c2.show();
33     return 0;
34 }