/* 

  Program: Menu-driven Calculator using switch (U2)

  What it does:

    - Reads two operands (double) and an operator choice (+, -, *, /).

    - Uses switch to perform the chosen operation; guards division by zero.

*/

#include <stdio.h>

int main(void) {

    double a, b, result;

    char op;

    printf("Enter two numbers (a b): ");

    if (scanf("%lf %lf", &a, &b) != 2) {

        printf("Invalid numbers.

");

        return 0;

    }

    printf("Choose operation (+ - * /): ");

    scanf(" %c", &op);

    switch (op) {

        case '+': result = a + b; printf("Result = %.6f

", result); break;

        case '-': result = a - b; printf("Result = %.6f

", result); break;

        case '*': result = a * b; printf("Result = %.6f

", result); break;

        case '/':

            if (b == 0.0) {

                printf("Error: Division by zero.

");

            } else {

                result = a / b; printf("Result = %.6f

", result);

            }

            break;

        default:

            printf("Unknown operation. Use + - * /.

");

    }

    return 0;

}