朱金付第十章编程

1.

#include <iostream>using namespace std;class circle{public:    virtual double funV(double r,double h=0){        return 3.1415926*r*r;    }};class yuanZhu:public circle{public:    double funV(double r,double h=0){        return 3.1415926*r*r*h;    }};class yuanZhui:public circle{public:    double funV(double r,double h=0){        return 3.1415926*r*r*h/3;    }};int main(){    circle c,*p;    yuanZhu z;    yuanZhui zhui;    p=&c;    cout<<p->funV(100,0)<<endl;    p=&z;    cout<<p->funV(100,100)<<endl;    p=&zhui;    cout<<p->funV(100,300)<<endl;    return 0;}

输出：

31415.9
3.14159e+06
3.14159e+06

2.

#include <iostream>using namespace std;class Complex{public:    double real,Image;    Complex(double r=0,double I=0){        real = r;        Image = I;    }    Complex operator-(Complex x1);    Complex &operator-=(Complex x2);    bool operator!=(Complex x3);    friend Complex operator+(Complex x4,Complex x5);    friend Complex &operator+=(Complex &x6,Complex x7);    friend bool operator==(Complex x8,Complex x9);    void show(){        cout<<real;        if (Image<0){            cout<<"-"<<Image<<"i"<<endl;        }else{            cout<<"+"<<Image<<"i"<<endl;        }    }};Complex Complex::operator-(Complex x1){    Complex newX;    newX.real = real - x1.real;    newX.Image = Image - x1.Image;    return newX;}Complex& Complex::operator-=(Complex x2){    real  = real - x2.real;    Image = Image - x2.Image;    return *this;}bool Complex::operator!=(Complex x3) {    if ((real!=x3.real)||(Image!=x3.Image)){        return true;    }else{        return false;    }}Complex operator+(Complex x4,Complex x5){    Complex newX;    newX.real = x5.real + x4.real;    newX.Image = x5.Image +x4.Image;    return newX;}Complex& operator+=(Complex &x6,Complex x7){    x6.real = x6.real +x7.real;    x6.Image = x6.Image + x7.Image;    return x6;}bool operator==(Complex x8,Complex x9){    if ((x8.real==x9.real)&&(x8.Image==x9.Image)){        return true;    }else{        return false;    }}int main(){    Complex c1(1,1),c2(1,1),c3(1,1),c4(1,1),c5(1,1),c6(1,1),c7(1,1),c8(1,1),c9(1,1),c10(1,1),c11(1,1);    c1=c2+c3;c1.show();  //2+2i    c4+=c5;c4.show();    //2+2i    c5=c6-c7;c5.show();  //0+0i    c6-=c7;c6.show();    //0+0i    cout<<(c8==c9)<<endl; //1    cout<<(c8!=c9)<<endl; //0    return 0;}

输出：

2+2i
2+2i
0+0i
0+0i
1
0


Process finished with exit code 0

3.定义一个三维坐标类，分别通过成员函数重载前置++和后置++运算符，通过友元函数重载前置--和后置--运算符，实现坐标值的+1和-1。main函数做测试。

#include <iostream>using namespace std;class coordinate{public:    double x,y,z;    coordinate(double x1=0,double y1=0,double z1=0){        x=x1;y=y1;z=z1;    }    coordinate operator++();    coordinate operator++(int);    friend coordinate operator--(coordinate &pp);    friend coordinate operator--(coordinate &pp,int);    friend ostream& operator<<(ostream &os,coordinate tt);};/*成员函数实现++*/coordinate coordinate::operator++() {    x++;y++;z++;    return *this;}coordinate coordinate::operator++(int) {    coordinate temp  = *this;    x++;y++;z++;    return temp;}/*友元函数实现++*/coordinate operator--(coordinate &pp) {    pp.x--;pp.y--;pp.z--;    return pp;}coordinate operator--(coordinate &pp,int) {    coordinate temp=pp;    pp.x--;pp.y--;pp.z--;    return temp;}ostream& operator<<(ostream& os,coordinate tt){    os<<"("<<tt.x<<","<<tt.y<<","<<tt.z<<")"<<endl;    return os;}int main(){    coordinate c1(1,1,1),c2(1,1,1),c3(1,1,1),c4(1,1,1);    cout<<(++c1);    cout<<(c2++);    cout<<(--c3);    cout<<(c4--);    return 0;}

4.

#include <iostream>#include <fstream>using namespace std;class student{public:    double num,csBase,cpp,cppProject;    char *name;    student(double n=0,char p1[50]="姓名未知",double cB=0,double cp=0,double cpP=0){        num = n;csBase=cB;cpp=cp;cppProject=cpP;        char *name = new char[50];        int i=0;        while(p1[i]){            *name++=p1[i++];        }    }    double ave(){        double ave =(csBase+cpp+cppProject)/3 ;        return ave;    }    friend istream &operator>>(istream &is,student &s1);};istream &operator>>(istream &is,student &s1){    cout<<"学号：";is>>s1.num;    cout<<"姓名：姓名+空格：";cin.getline(s1.name,50,' ');    cout<<"计算机基础：";is>>s1.csBase;    cout<<"C++程序设计：";is>>s1.cpp;    cout<<"C++课程设计：";is>>s1.cppProject;    return is;}int main(){    student student1;    cin>>student1;    cout<<"平均成绩为"<<student1.ave();    return 0;}