Write a shell script called atm.csh (in C shell) similar to the ones used in ATM machines. Essentially your script is to handle a person's savings and checking accounts and should handle the following services:

Transfer from savings account to checking account

Transfer form checking account to savings account

Cash withdrawal from either account

Balance statements for both the accounts

Assume that the ATM machine recognizes a unique 3-digit personal identification number (PIN). In your initial screen you are to first ask the user to type in his/her PIN as follows:

*** Welcome to Cal Poly's ATM ****

Please enter your PIN:

In response to this, the user has to enter a valid PIN. Assume that the only legal PIN is: 111

If any number besides this PIN is entered, the screen is to be cleared and the same screen to be redisplayed. The user then gets a second chance to enter a valid PIN. If an illegal PIN is entered three consecutive, the following message:

Too many illegal PINs. Try later again.

should appear on the screen and your script must terminate. If the entered PIN is a legal value, the main menu is to be displayed as follows:

*** Welcome To Cal Poly's ATM System ***

(1) Transfer from checking account to savings account

(2) Transfer from savings account to checking account

(3) Savings account balance

(4) Checking account balance

(5) Withdraw Cash from either account

(6) Exit

==> Please select option (1-6):

The following are some of the guidelines you should follow:

Guidelines

-- The main menu is to continue to be displayed until user selects option 6. At this point a message such as

Thank you for using the ATM system.

should appear and your program execution is to be terminated.

-- Users have to select options 1, 2, 3, 4, 5 or 6. Redisplay the menu if any number outside the range 1 to 6 is entered (Hint: Use the command clear after every menu option is complete and before displaying the menu again)

-- Write functions (if the shell allows for user defined functions) for displaying menu options, for transferring, and withdrawing from the accounts.

-- Withdrawal (selection 5) should ask whether the user wants to withdraw from checking account or saving account and should subtract the amount specified from the appropriate account.

-- Savings and checking accounts both have initial balance of $1000.00

-- Any transfer is allowed only if it can be honored. For example, if the savings account balance is $500.00 and the user requests to transfer $550.00 from that savings account to the checking account an appropriate message such as

"Transaction not completed"

should be displayed and the current balance of that account should be printed.

The screen is to be cleared and the main menu to be displayed.