This Java program simulates ATM operations, allowing users to check their balance, deposit money, or withdraw funds through a menu-driven interface. The user can make transactions until they decide to quit by entering an appropriate option. The program handles insufficient funds during withdrawal attempts and displays the updated balance after each transaction.

1. /**
* The java program that simulates ATM operations.
* The program display a menu of choices.
* The prompt to enter operation to perform
* and then print the balance after the transaction
* to console.
* */
//AtmSimDoLoop.java
import java.util.Scanner;
public class AtmSimDoLoop {
public static void main(String[] args) {
//Create a Scanner class object
Scanner scanner=new Scanner(System.in);
//declare variables
double balance=0;
int userChoice;
double deposit;
double withdrawl;
//set repeat =true
boolean repeat=true;
//prompt and repeat until user enters 4 to exit
do {
System.out.println("Enter the number of your desired transaction type.");
System.out.println("1.Balance");
System.out.println("2.Deposit");
System.out.println("3.Withdrawl");
System.out.println("4.Quit");
userChoice=Integer.parseInt(scanner.nextLine());

2. //using switch case to select an appropriate choice
switch (userChoice) {
case 1:
System.out.println("Your current balance is "+balance);
break;
case 2:
System.out.println("Enter the amount of the deposit ");
deposit=Double.parseDouble(scanner.nextLine());
balance+=deposit;
System.out.println("Your current balance is "+balance);
break;
case 3:
System.out.println("Enter the amount of the withdrawl ");
withdrawl=Double.parseDouble(scanner.nextLine());
if(withdrawl<=balance)
{
balance-=withdrawl;
System.out.println("Your current balance is "+balance);
}
else
System.out.println("Insufficient funds. Your current balance is "+balance+".");
break;
case 4:
System.out.println("Good-bye.");
//set repeat=false
repeat=false;
}
} while (repeat);
}//end of main
}//end of class AtmSimDoLoop
------------------------------------------------------------------------------------------------------------
Sample output:
Enter the number of your desired transaction type.

3. 1.Balance
2.Deposit
3.Withdrawl
4.Quit
1
Your current balance is 0.0
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
2
Enter the amount of the deposit
500
Your current balance is 500.0
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
3
Enter the amount of the withdrawl
300
Your current balance is 200.0
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
3
Enter the amount of the withdrawl
300
Insufficient funds. Your current balance is 200.0.
Enter the number of your desired transaction type.
1.Balance
2.Deposit

4. 3.Withdrawl
4.Quit
4
Good-bye.
Solution
/**
* The java program that simulates ATM operations.
* The program display a menu of choices.
* The prompt to enter operation to perform
* and then print the balance after the transaction
* to console.
* */
//AtmSimDoLoop.java
import java.util.Scanner;
public class AtmSimDoLoop {
public static void main(String[] args) {
//Create a Scanner class object
Scanner scanner=new Scanner(System.in);
//declare variables
double balance=0;
int userChoice;
double deposit;
double withdrawl;
//set repeat =true
boolean repeat=true;
//prompt and repeat until user enters 4 to exit
do {
System.out.println("Enter the number of your desired transaction type.");
System.out.println("1.Balance");

5. System.out.println("2.Deposit");
System.out.println("3.Withdrawl");
System.out.println("4.Quit");
userChoice=Integer.parseInt(scanner.nextLine());
//using switch case to select an appropriate choice
switch (userChoice) {
case 1:
System.out.println("Your current balance is "+balance);
break;
case 2:
System.out.println("Enter the amount of the deposit ");
deposit=Double.parseDouble(scanner.nextLine());
balance+=deposit;
System.out.println("Your current balance is "+balance);
break;
case 3:
System.out.println("Enter the amount of the withdrawl ");
withdrawl=Double.parseDouble(scanner.nextLine());
if(withdrawl<=balance)
{
balance-=withdrawl;
System.out.println("Your current balance is "+balance);
}
else
System.out.println("Insufficient funds. Your current balance is "+balance+".");
break;
case 4:
System.out.println("Good-bye.");
//set repeat=false
repeat=false;
}
} while (repeat);

6. }//end of main
}//end of class AtmSimDoLoop
------------------------------------------------------------------------------------------------------------
Sample output:
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
1
Your current balance is 0.0
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
2
Enter the amount of the deposit
500
Your current balance is 500.0
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
3
Enter the amount of the withdrawl
300
Your current balance is 200.0
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
3

7. Enter the amount of the withdrawl
300
Insufficient funds. Your current balance is 200.0.
Enter the number of your desired transaction type.
1.Balance
2.Deposit
3.Withdrawl
4.Quit
4
Good-bye.