Question

用C++语言定义一个类，实现加减乘除运算

// class2.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <IOSTREAM>
using namespace std;

class nHour
{
public:
nHour();
public:
double add(double a, double b);
double div(double a, double b);
};
double add(double a, double b)
{

return a + b;
}
double subtract(double a, double b)
{
return a - b;
}
int main()
{
nHour my;
double sum = 0;
sum = my.add(10, 5);
cout << "10+5 = " << sum << endl;

sum = my.subtract(10, 5);//包含的有为什么会说没有 求解
cout << "10-5 = " << sum << endl;
}

Answer 1

#include <iostream.h> class CMy_Math { public: CMy_Math(); ~CMy_Math(); public: double add(double a,double b); //加法 double div(double a,double b);//除法 double subtract(double a,double b);//减法 double mult(double a,double b); //乘法 }; CMy_Math::CMy_Math() { } CMy_Math::~CMy_Math() { } double CMy_Math::add(double a,double b) { return a+b; } double CMy_Math::subtract(double a,double b) { return a-b; } double CMy_Math::mult(double a,double b) { return a*b; } double CMy_Math::div(double a,double b) { if ( 0.0 != b) //b不能为0.0 return a/b; } int main(double argc, char* argv[]) { CMy_Math my; double sum=0; sum= my.add(10,5); cout<<"10+5 = "<<sum<<endl; sum= my.subtract(10,5); cout<<"10-5 = "<<sum<<endl; sum= my.subtract(10,5); cout<<"10*5 = "<<sum<<endl; sum= my.div(10,5); cout<<"10/5 = "<<sum<<endl; return 0; }