int main()
{
char op;
float num1, num2;

cout << "输入运算符：+、-、*、/ : ";
cin >> op;

cout << "输入两个数: ";
cin >> num1 >> num2;

switch(op)
{
case ‘+‘:
cout << num1+num2;
break;

case ‘–‘:
cout << num1–num2;
break;

case ‘*‘:
cout << num1*num2;
break;

case ‘/‘:
if (num2 == 0)
{
cout << "error不能除以零";
break;
}
else
{
cout << num1 / num2;
break;
}

default:
// 如果运算符不是 +, -, * 或 /, 提示错误信息
cout << "Error! 请输入正确运算符。";
break;
}

return 0;
}