NBC 103 • Practical #3
Menu-Driven Arithmetic Calculator
Aim: To implement a menu-driven calculator using switch-case for basic arithmetic operations (+, -, *, /).
Step-by-Step Algorithm & Logic
- 11. Start and display menu: 1. Add, 2. Subtract, 3. Multiply, 4. Divide.
- 22. Read user choice and operands num1, num2.
- 33. Switch on choice: case 1 -> add, case 2 -> sub, case 3 -> mult, case 4 -> div (check div by zero).
- 44. Include break statement after every case to prevent fall-through.
- 55. Provide default case for invalid menu inputs.
#include <stdio.h>
int main(void) {
int choice = 3;
double num1 = 12.5, num2 = 4.0;
printf("=== BCA CALCULATOR (Choice: %d) ===\n", choice);
printf("Operands: %.2lf and %.2lf\n", num1, num2);
switch (choice) {
case 1:
printf("Result: %.2lf + %.2lf = %.2lf\n", num1, num2, num1 + num2);
break;
case 2:
printf("Result: %.2lf - %.2lf = %.2lf\n", num1, num2, num1 - num2);
break;
case 3:
printf("Result: %.2lf * %.2lf = %.2lf\n", num1, num2, num1 * num2);
break;
case 4:
if (num2 != 0)
printf("Result: %.2lf / %.2lf = %.2lf\n", num1, num2, num1 / num2);
else
printf("Error: Division by Zero is undefined!\n");
break;
default:
printf("Invalid Option selected.\n");
}
return 0;
}Sample Input:
Choice = 3, num1 = 12.5, num2 = 4.0
Sample Output:
Result: 12.50 * 4.00 = 50.00
Practical Exam Viva Questions (Exp #3)
1