Menu Driven C++ Program for a Simple Calculator

// 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; 
}