Example: Basic Bank Account Transactions in C++

// Basic Bank Account Transactions
#include <iostream> // Required for input/output operations
#include <limits>   // Required for numeric_limits to clear input buffer

using namespace std;

int main() {
    double balance = 1000.00; // Initial account balance
    int choice;                // To store user's menu choice
    double amount;             // To store deposit or withdrawal amount

    cout << "Welcome to the Simple C++ Bank Account System!" << endl;

    // Loop to keep the program running until the user chooses to exit
    do {
        // Display the main menu
        cout << "\n--- Main Menu ---" << endl;
        cout << "1. Deposit Cash" << endl;
        cout << "2. Withdraw Cash" << endl;
        cout << "3. Check Balance" << endl;
        cout << "4. Exit" << endl;
        cout << "Enter your choice: ";
        cin >> choice;

        // Clear input buffer in case of invalid input (e.g., characters)
        // This prevents infinite loops if non-numeric input is given for 'choice'
        if (cin.fail()) {
            cin.clear(); // Clear the error flag
            cin.ignore(numeric_limits<streamsize>::max(), '\n'); // Discard invalid input
            cout << "Invalid input. Please enter a number." << endl;
            choice = 0; // Reset choice to an invalid option to re-display menu
            continue;   // Skip to the next iteration of the loop
        }

        // Process user's choice using a switch statement
        switch (choice) {
            case 1: // Deposit Cash
                cout << "\nEnter amount to deposit: $";
                cin >> amount;
                if (cin.fail() || amount <= 0) {
                    cin.clear();
                    cin.ignore(numeric_limits<streamsize>::max(), '\n');
                    cout << "Invalid deposit amount. Please enter a positive number." << endl;
                } else {
                    balance += amount; // Add amount to balance
                    cout << "Deposit successful! New balance: $" << balance << endl;
                }
                break;

            case 2: // Withdraw Cash
                cout << "\nEnter amount to withdraw: $";
                cin >> amount;
                if (cin.fail() || amount <= 0) {
                    cin.clear();
                    cin.ignore(numeric_limits<streamsize>::max(), '\n');
                    cout << "Invalid withdrawal amount. Please enter a positive number." << endl;
                } else if (amount > balance) {
                    cout << "Insufficient funds! Current balance: $" << balance << endl;
                } else {
                    balance -= amount; // Subtract amount from balance
                    cout << "Withdrawal successful! New balance: $" << balance << endl;
                }
                break;

            case 3: // Check Balance
                cout << "\nYour current balance is: $" << balance << endl;
                break;

            case 4: // Exit Program
                cout << "\nThank you for using the Simple Bank Account System. Goodbye!" << endl;
                break;

            default: // Invalid choice
                cout << "Invalid choice. Please try again." << endl;
                break;
        }
    } while (choice != 4); // Continue loop until user chooses to exit (option 4)

    return 0; // Indicate successful program execution
}