#include  <stdio.h>
int main(void)
{
    int    data1, data2;
    char  op;
    printf("Please enter an expression:");
    scanf("%d%c%d", &data1, &op, &data2);  
switch (op)
{
case '+':
   printf ("%d+%d=%d",data1,data2,data1+data2);
case '-':
    break;
    printf ("%d-%d=%d",data1,data2,data1-data2);
   break;
case '*':
    printf ("%d*%d=%d",data1,data2,data1*data2);
break; 
case '/':
    if (data2==0)
      printf ("除数为0，请重新输入");
    else 
       printf ("%d/%d=%d",data1,data2,data1/data2);
break; 
default: 
   printf ("输入错误，请重新输入");



}

    return 0;
}