Question

请教c++高手，帮忙看看哪错了，感谢了啊。

#include<iostream>
using namespace std;
class Car;
class Boat
{
public:
void getWeight1()
{
cout<<"input the Boat's Weight:";
cin>>weight1;
}
int getWeightToal(Car &w);
private:
int weight1;
};

class Car
{
public:
void getWeight1()
{
cout<<"input the Boat's Weight:";
cin>>weight2;
}

friend int getWeightToal(Boat &w)
{
int toalw;
toalw=weight2+w.weight1;
cout<<toalw;

}

private:
int weight2;
};
int main()
{
void getWeight1();
void getWeight2();
cout<<"the toalweight is:";
int getWeightToal();
return 0;
}

Answer 1

main 主函数调用void getWeight1();void getWeight2();int getWeightToal();错误，
1.函数调用时不用表明返回值类型，这里的void ,int都不要用
2这三个函数都是类的成员函数，在类之外调用时，要先建立相应的类的对象，在通过建立的对象调用成员函数

Answer 2

补充一楼， car类里的getWeightToal是car类的友元函数，只能通过对象访问car类的私有成员，而不能访问boat类的私有成员，