c语言-简单四则运算器

假定输入都是整数且不考虑运算符优先级

#include<stdio.h>
#include<stdlib.h>

int main()
{
    int sum, x;
    char op;
    scanf_s("%d%c", &sum, &op,3);
    while (op != '=')
    {
        scanf_s("%d", &x);
        switch (op)
        {
        case'+':
            sum += x;
            break;
        case'-':
            sum -= x;
            break;
        case'*':
            sum *= x;
            break;
        case'/':
            if (x == 0)
            {
                printf("除法分母为0！\n");
                return 0;
            }
            else
            {
                sum /= x;
                break;
            }
        default:
            printf("非法输入！\n");
            return 0;
        }
        scanf_s("%c", &op,1);
    }
    printf("%d\n", sum);

    system("pause");
    return 0;
}