C++语言，我搞了半天还是不明白，求教，求过程

没明白什么？

这个简单，大晚上了，给你回答完睡觉啊

#include "stdafx.h"
#include
#include
using namespace std;

class calculator
{
public:
calculator(double num1, double num2)
:number1(num1), number2(num2)
{

}
double add()
{
return number1 + number2;
}

double sub()
{
return number1 - number2;
}

double mul()
{
return number1 * number2;
}

double div()
{
if (number2)
return number1 / number2;

return 0;
}

private:
double number1;
double number2;
};

int main(int argc, _TCHAR* argv[])
{
cout << "place input 2 number:";
double number1 = 0;
double number2 = 0;
cin >> number1 >> number2;

calculator calc(number1, number2);

cout << "add:" << calc.add() << endl;
cout << "sub:" << calc.sub() << endl;
cout << "mul:" << calc.mul() << endl;
cout << "div:" << calc.div() << endl;

system("pause");
return 0;
}