5-41 Simple Calculator (20 points)

5-41 Simple Calculator (20 points)

Simulates the work of a simple arithmetic device. Assuming that the calculator can only perform subtraction operations, the operands and results are integers, and the four operators have the same precedence, calculated in left-to-right order. Input Format:

The input gives a arithmetic calculation in a row, with no spaces and at least one operand. An equal sign "=" indicates the end of the input. output Format:

Outputs the result of a calculation in a row, or if the division denominator is 0 or has an illegal operator, the error message "error" is output. Input Sample:

1+2*10-10/2=

Sample output:

10

//

/* Subtraction operation of the analog operator, however, here, the
arithmetic rule no longer applies, calculated in the order of number and operation symbols,
such as, 1+2*10-10/2=10
*/
#include "stdio.h"
int main ()
{
    int value1,value2;
    int sum=0;
    char ch;
    scanf ("%d", &value1);
    while ((Ch=getchar ()) = ' = ')
    {
        scanf ("%d", &value2);
        if (ch== '/' &&value2==0) {
                printf ("error\n");
                return 0;

        }
        Switch (CH)
        {case
            ' + ': sum=value1+value2;break;
            Case '-': sum=value1-value2;break;
            Case ' * ': sum=value1*value2;break;
            Case '/': Sum=value1/value2;break;
            default:printf ("error\n"); return 0;

        }
        value1=sum;


    }
    printf ("%d\n", value1);
    return 0;
}