Main.java

import java.util.Scanner;

public class Main {

	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {

		// Java Banking Program

		// Declare Variables
		double balance = 0;
		boolean isRunning = true;
		int choice;

		while (isRunning) {
			// Menu
			System.out.println("***************");
			System.out.println("BANKING PROGRAM");
			System.out.println("***************");
			System.out.println("1. Show Balance");
			System.out.println("2. Deposit");
			System.out.println("3. Withdraw");
			System.out.println("4. Exit");
			System.out.println("***************");

			// GET AND PROCESS Users Choice
			System.out.print("Enter Your Choice (1-4) : ");
			choice = sc.nextInt();

			switch (choice) {
				case 1:
					showBalance(balance);
					break;
				case 2:
					balance += deposit();
					break;
				case 3:
					balance -= withdraw(balance);
					break;
				case 4:
					isRunning = false;
					break;
				default:
					System.out.println("INVALID CHOICE");
			}
		}

		System.out.println("***************************");
		System.out.println("Thank you! Have a nice day!");
		System.out.println("***************************");

		// EXIT
		sc.close();
	}

	// SHOW BALANCE
	static void showBalance(double balance) {
		System.out.println("\n*************************");
		System.out.printf("Your Balance is : $%.2f", balance);
		System.out.println("\n*************************\n\n");
	}

	// DEPOSIT
	static double deposit() {
		double amount;

		System.out.print("Enter an amount to be deposited: ");
		amount = sc.nextDouble();

		if (amount < 0) {
			System.out.println("Amount Can't be Negative.");
			return 0;
		} else {
			return amount;
		}
	}

	// WITHDRAW
	static double withdraw(double balance) {
		double amount;

		System.out.println("Enter amount to be Withdrawn : ");
		amount = sc.nextDouble();

		if (amount > balance) {
			System.out.println("INSUFFICIENT FUNDS");
			return 0;
		} else if (amount < 0) {
			System.out.println("Amount Can't be Negative.");
			return 0;
		} else {
			return amount;
		}
	}
}