设计并实现一个简单的计算器c++

#include "stdafx.h"
#include
#include
using namespace std;
double myAdd(double x,double y)//+
{
 return (x+y); //return x+y;
}
double mySub(double x,double y)
{
 return (x-y);
}
double myMultiple(double x,double y)
{
 return (x * y);
}
double myDiv(double x,double y)
{
 return (x / y);
}
double myMod(int x,int y)
{
    return(x % y);
}
double myExponible(double x,double y)
{
 return(pow(x,y));
}
int _tmain(int argc, _TCHAR* argv[])
{
 double a,b;
 char oper;//operation,操作符，operand 操作数
 
 cout<<"请输入2个实数和1个四则运算的符号(同时为0，退出程序)："< loop:
 cin>>a>>b;
 cin>>oper;
    while (a!=0&&b!=0){
 if(oper=='+'){
  double r1=myAdd(a,b);
  cout<  }
 }
 else if(oper=='%'){
  if(b!=0){
   double r5=myMod(a,b);
   cout<  }
 }
 else if(oper=='N'){
  if(b>=0){
   double r6=myExponible(a,b);
   cout< }
 goto loop;
 }

 system("pause");
 return 0;
}