Bank Account Program

Question

I am working on making a program to simulate bank transactions. I have to ask the user if they want to deposit, withdrawal, or transfer.

When I deposit a certain amount (for example 1000), it says my balance is 1000. Then I ask to withdrawal a number like 400 it says my balance is -400. After all that I thought maybe I have to check my balance and then it will give me the correct balance of what should be 600, but it says 0. For instance, see this transcript:

I was thinking because in my code (shown below) I made the balance = 0 but if I take the = 0 away and try to run the program it says it needs to be initialized.

I am stuck and I want to figure it out. Please don't post the entire code corrected. I want to fix it myself and learn!

import java.util.Scanner;

public class BankTransactions {


    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        int num;

        do {

            double balance = 0;
            double amount;

            System.out.println("Type Number");
            System.out.println("1. Deposit");
            System.out.println("2. Withdrawal");
            System.out.println("3. Balance");
            System.out.println("4. Exit");
            num = scan.nextInt();

            if (num == 1) {
                System.out.println("Enter amount to deposit: ");
                amount = scan.nextDouble();

                // Add the amount to the balance
                balance += amount;
                System.out.println("Your balance is");
                System.out.println(balance);


            } else if (num == 2) {

                System.out.println("Enter amount to withdrawal: ");
                amount = scan.nextDouble();

                // Remove the amount from the balance
                balance -= amount;
                System.out.println("Your balance is");
                System.out.println(balance);

            } else if (num == 3) {


                System.out.println("Your Balance");
                System.out.println(balance);

            }



        } while (num != 4);

        System.out.println("Good Bye!");

    }
}

Answer 1

Every time the do{...} while{...} is executed, you are setting balance=0. You should take it out the loop.

double balance = 0;

do{
...

Answer 2

You are initializing balance to 0 within the do loop, so it resets to zero each time around.

Move the line balance = 0 to above the while loop.