实验3

4-11.

#include<iostream>
using namespace std;

class rectangle{
    public:
        rectangle (int a,int b);
        rectangle(){
            l=0;
            w=0;
        }
        rectangle(rectangle &p);
        void SET(int a,int b);
        void COUNT();
    private:
        int l,w;
};

rectangle::rectangle(rectangle &p){
    l=p.l;
    w=p.w;
}

rectangle::rectangle(int a,int b){
    l=a;
    w=b;
}

void rectangle::SET(int a,int b){
    l=a;
    w=b;
}

void rectangle::COUNT(){
    cout<<"l+w="<<l+w<<endl;
}

int main()
{
    rectangle one;
    int a,b;
    cout<<"ÊäÈ볤¡¢¿í"<<endl;
    cin>>a>>b;
    one.SET(a,b);
    one.COUNT();
    return 0;
}

4-20.

#include<iostream>
using namespace std;

class Complex{
    public:
        Complex(double a,double b);
        Complex(double a);
        void add(Complex &p){
            real=real+p.real;
            imaginary=imaginary+p.imaginary;
        };
        void show();
    private:
        double real,imaginary;
};

Complex::Complex(double a,double b){
    real=a;
    imaginary=b;
}

Complex::Complex(double a){
    real=a;
}

void Complex::show(){
    cout<<real<<"+"<<imaginary<<"i"<<endl;
}

int main(){
    Complex c1(3,5);
    Complex c2=4.5;
    c1.add(c2);
    c1.show();
    return 0;
}