c语言 计算器程序

#include <stdio.h>

double calculator (double a, double b, char operation)
{
    if (operation == '+')
    {
        return a+b;
    }
    else if (operation == '-')
    {
        return a-b;
    }
    else if (operation == '*')
    {
        return a*b;
    }
    else if (operation == '/')
    {
        if (b==0)
        {
            printf("除数不能为 0!!!\n");
            return 0;
        }
        else
        {
            return a/b;
        }
    }
    else
    {
        printf("输入错误 \n");
        return 0;
    }
}
int main()
{
    double a ,b;
    char operation;
    scanf("%lf%c%lf",&a,&operation,&b);
    printf("%.2lf\n",calculator(a, b, operation));
    return 0;
}