Simple Calc

#include <stdio.h>
#include <math.h>
void main() // ~ program to make a simple calculator.
{
    static double a, b;
    char op;

    scanf("%lf", &a);
    scanf(" %c", &op);
    scanf("%lf", &b);

    do
    {
        switch (op)
        {

        case '+': // ? ADDITION
            printf("%.2lf", a + b);
            a = a + b;
            scanf(" %c", &op);
            scanf("%lf", &b);
            break;

        case '-': // ? SUBTRACTION
            printf("%.2lf", a - b);
            a = a - b;
            scanf(" %c", &op);
            scanf("%lf", &b);
            break;

        case '*': // ? MULTIPLICATION
            printf("%.2lf", a * b);
            a = a * b;
            scanf(" %c", &op);
            scanf("%lf", &b);
            break;

        case '/': // ? DIVISION
            printf("%.2lf", a / b);
            a = a / b;
            scanf(" %c", &op);
            scanf("%lf", &b);
            break;

        case '%': // ? MODULO DIVISION
            printf("%.2lf", fmod(a, b));
            a = fmod(a, b);
            scanf(" %c", &op);
            scanf("%lf", &b);
            break;

        case '^': // ? EXPONENT VALUE
            printf("%.2lf", pow(a, b));
            a = pow(a, b);
            scanf(" %c", &op);
            scanf("%lf", &b);
            break;
        }
    } while (op != '=');

    // ^ Press '=' twice to end the program.

    if (op == '=')
        printf("DONE");
}

// & THIS CODE IS WRITTEN BY MANJUNATH MGM.