Menu Driven C++ Program for a Simple Calculator

**Problem Statement:**

Write a menu-driven program using the Switch case to calculate the following:

- Addition of two numbers
- Difference between two numbers
- Product of two numbers
- Division of two numbers
- HCF of two numbers
- LCM of two numbers

**Examples:**

Input:num1 = 5, num2 = 7, choice = 1Output:Sum is 12Input:num1 = 5, num2 = 7, choice = 5Output:GCD is 1

**Implementation:**

`// C++ program to illustrate` `// Menu-Driven program using Switch-case` ` ` `#include <bits/stdc++.h>` `using` `namespace` `std;` ` ` `// Function to display the menu` `void` `menu()` `{` ` ` `cout << ` `"Press 1 to calculate Sum of Numbers\n"` `;` ` ` `cout << ` `"Press 2 to calculate Difference of Numbers\n"` `;` ` ` `cout << ` `"Press 3 to calculate Product of numbers\n"` `;` ` ` `cout << ` `"Press 4 to calculate Division of numbers\n"` `;` ` ` `cout << ` `"Press 5 to calculate HCF of numbers\n"` `;` ` ` `cout << ` `"Press 6 to calculate LCM of numbers\n"` `;` ` ` `cout << ` `"Press 7 to exit\n"` `;` `}` ` ` `// Function to calculate and display the result` `void` `result(` `int` `choice, ` `int` `a, ` `int` `b)` `{` ` ` ` ` `// Display the result` ` ` `switch` `(choice) {` ` ` `case` `1: {` ` ` `cout << ` `"Sum is "` `<< (a + b) << ` `"\n"` `;` ` ` `break` `;` ` ` `}` ` ` `case` `2: {` ` ` `cout << ` `"Difference is "` `<< (a - b) << ` `"\n"` `;` ` ` `break` `;` ` ` `}` ` ` `case` `3: {` ` ` `cout << ` `"Product is "` `<< (a * b) << ` `"\n"` `;` ` ` `break` `;` ` ` `}` ` ` `case` `4: {` ` ` `cout << ` `"Division is "` `<< (a / b) << ` `"\n"` `;` ` ` `break` `;` ` ` `}` ` ` `case` `5: {` ` ` `cout << ` `"GCD is "` `<< __gcd(a, b) << ` `"\n"` `;` ` ` `break` `;` ` ` `}` ` ` `case` `6: {` ` ` `cout << ` `"LCM is "` ` ` `<< ((a * b) / __gcd(a, b))` ` ` `<< ` `"\n"` `;` ` ` `break` `;` ` ` `}` ` ` `case` `7: {` ` ` `cout << ` `"Thank you\n"` `;` ` ` `break` `;` ` ` `}` ` ` `default` `:` ` ` `printf` `(` `"Wrong Input\n"` `);` ` ` `}` `}` ` ` `int` `main()` `{` ` ` ` ` `// Get the two numbers` ` ` `int` `a = 5, b = 7;` ` ` ` ` `int` `choice, res;` ` ` ` ` `// Display the menu` ` ` `menu();` ` ` ` ` `// Enter the choice` ` ` `cout << ` `"Enter your choice:\n"` `;` ` ` `choice = 1;` ` ` `cout << ` `"Choice is "` `<< choice << endl;` ` ` ` ` `// Display the result` ` ` `// according to the choice` ` ` `result(choice, a, b);` ` ` ` ` `return` `0;` `}` |

**Output:**

Press 1 to calculate Sum of Numbers Press 2 to calculate Difference of Numbers Press 3 to calculate Product of numbers Press 4 to calculate Division of numbers Press 5 to calculate HCF of numbers Press 6 to calculate LCM of numbers Press 7 to exit Enter your choice: Choice is 1 Sum is 12

**Time Complexity:** O(n).

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