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;
}