第三章例3-11

#include<stdio.h>
int main(void)
{
   double value1,value2;
   char op;

   printf("Type in an expression:");
   scanf("%lf%c%lf",&value1,&op,&value2);
   if(op=='+')
       printf("=%.2f\n",value1+value2);
   else if(op=='-')
       printf("=%.2f\n",value1-value2);
   else if(op=='*')
       printf("=%.2f\n",value1*value2);
   else if(op=='/')
        if(value2!=0)
            printf("=%.2f\n",value1/value2);
        else
            printf("Divisor can not be 0!\n");
    else
       printf("Unknown operator!\n");
   return 0;
}