2-3.cpp

用类进行图形的关系判断

#include <iostream>     
class Car;                                                          /*前置Car类定义*/ 
class Boat                                                          /*Boat类定义*/ 
{
    public:                                                         /*外部借口，公有成员函数*/ 
        friend float TotalWeight(Boat &b,Car &c);
        Boat (Boat &b)                                              /*拷贝构造函数*/ 
        {
            weight=b.weight;
        }
        Boat (float w=0)                                            /*构造函数*/  
        {
            weight=w;
        }
        float GetW() {return weight;}
    private:
        float weight;                                               /*同名私有数据*/ 
};

class Car
{
    public:                                                         /*外部借口，公有成员函数*/ 
        friend float TotalWeight(Boat &b,Car &c);
        Car (Car &c)                                                /*拷贝构造函数*/ 
        {
            weight=c.weight;
        }
        Car (float w=0)                                             /*构造函数*/  
        {
            weight=w;
        }
        float GetW() {return weight;}
    private:
        float weight;                                               /*同名私有数据*/ 
};

float TotalWeight(Boat &b,Car &c)
{
    return b.weight+c.weight;
}
    
int main()
{
    float w1,w2;
    char temp;
    std::cout << "请输入两个重量w1,w2:" << std::endl;
    std::cin >>w1>>w2;
    Boat b(w1);
    Car c(w2);
    std::cout << "两者的重量和:" << TotalWeight(b,c) << std::endl;
    system("pause");
    return 0;
}