Question

请帮忙看看这个C++程序那里错了

程序代码如下，我想用C++的类实现一个简单计算器的功能，但是编译时总是出错。请帮忙看看那里错了！谢谢
#include "iostream.h"
class cal;
int main()
{
float a,b,c;
char m;
cal jisuanqi;
cout<<"输入两个数a,b："<<endl;
cin>>a>>b;
cout<<"输入运算符号（+、-、*、/）："<<endl;
cin>>m;
switch (m)
{
case '+':
cout<<jisuanqi.jia(a,b)<<endl;
break;
case '-':
cout<<jisuanqi.jian(a,b)<<endl;
break;
case '*':
cout<<jisuanqi.cheng(a,b)<<endl;
break;
case '/':
cout<<jisuanqi.chu(a,b)<<endl;
break;
default:
cout<<"程序有错误！！"<<endl;

}
return 0;

}
class cal
{
public:
float jia(float a,float b)
{
return a+b;
}
float jian(float a,float b)
{
return a-b;
}
float cheng(float a,float b)
{
return a*b;
}
float chu(float a,float b)
{
if(b==0)
{
cout<<"错误！除数不能为零！！"<<endl;
}
else
{
return a/b;
}
}
};

Answer 1

你用下面这个

#include "iostream.h"
class cal
{
public:
float jia(float a,float b)
{
return a+b;
}
float jian(float a,float b)
{
return a-b;
}
float cheng(float a,float b)
{
return a*b;
}
float chu(float a,float b)
{
if(b==0)
{
cout<<"错误！除数不能为零！！"<<endl;
}
else
{
return a/b;
}
}
};

int main()
{
float a,b,c;
char m;
cal jisuanqi;
cout<<"输入两个数a,b："<<endl;
cin>>a>>b;
cout<<"输入运算符号（+、-、*、/）："<<endl;
cin>>m;
switch (m)
{
case '+':
cout<<jisuanqi.jia(a,b)<<endl;
break;
case '-':
cout<<jisuanqi.jian(a,b)<<endl;
break;
case '*':
cout<<jisuanqi.cheng(a,b)<<endl;
break;
case '/':
cout<<jisuanqi.chu(a,b)<<endl;
break;
default:
cout<<"程序有错误！！"<<endl;

}
return 0;

}

还有引用标准库最好用#include <iostream.h>

Answer 2

把class cal放到main函数前面去...