#include <iostream>

using namespace std;

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 '/':

            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 ;

}