hey guys so this is my program, I need to notify the user that if hhe/she enters a letter other than w d b or w that is an invalid request. what ive done so far does this, but when i input a number to the dollars_withdraw or dollars_deposit or account_balance the program will do the transaction but also add the "invalid request" before going back to main loop. how do i change it so the program wont do that for numerical inputs for the withdraw deposit and balance?: // Atm machine.cpp : Defines the entry point for the console application. #include <iostream> #include <string> using namespace std; int main () { char user_request; string user_string; double account_balance, dollars_withdraw, dollars_deposit; account_balance = 5000; while(account_balance >0) { cout << "Would you like to [W]ithdraw, [D]eposit, Check your [b]alance or [Q]uit?" << endl; cin >> user_string; user_request= user_string[0]; if(user_request == 'w' || user_request== 'W') { cout << "How much would you like to withdraw?" << endl; cin >> dollars_withdraw; if (dollars_withdraw > account_balance || dollars_withdraw <0) cout << "Invalid transaction" << endl; else account_balance = account_balance - dollars_withdraw; cout << "Your new balance is $" << account_balance << endl; } if (user_request == 'd' || user_request== 'D') { cout << "How much would you like to deposit?" << endl; cin >> dollars_deposit; if (dollars_deposit <0) cout << "Invalid transaction" << endl; else account_balance= account_balance + dollars_deposit; cout << "Your new balance is $" << account_balance << endl; } if(user_request == 'b' || user_request == 'B') { account_balance= account_balance; cout << "Your available balance is $" << account_balance << endl; } if(user_request == 'q' || user_request == 'Q') break; else cout << "Invalid request " << endl; } cout << "Goodbye" << endl; return 0; }