# include <stdio.h>

int main(void)
{
    float a, b;
    char c;

    printf("请输入表达式: a(+-*/)b \n");
    scanf("%f %c %f", &a, &c, &b);

    switch (c)
    {
          case'+':
          printf("a+b = %f\n", a+b);
          break;

          case'-':
          printf("a-b = %f\n", a-b);
          break;

          case'*':
          printf("a*b = %f\n", a*b);
          break;

          case'/':
          printf("a/b = %f\n", a/b);
          break;

          default:
          printf("输入错误！\n");

    }

    return 0;
}