Write a function called withdraw (in the file 'withdraw.m') that simulates withdrawing money from a bank account. The function takes a single input argument, a positive scaler double value. If the user passes a value that is not scaler or is not greater than 0, your function should throw an error.

The function should access a global variable called BALANCE. Subtract the amount of the withdrawal from the BALANCE variable. If the subtraction would take BALANCE to less than 0, leave BALANCE unchanged and throw an error. Also, if BALANCE is not yet defined, thow an error.

Finally you are limited to 5 withdrawals from your bank account. Use a persistent variable to store how many times the withdrawal function has been used. On the fifth and all subsequent calls to the function it should automatically throw an error and not perform the withdrawal.

The function should return only one value, the number of withdrawals remaining.

From the 'hw4.m' file set the global value BALANCE to some initial value. Then show some example calls to the withdraw function, followed by a display of the remaining value of BALANCE. You should demonstrate the various error conditions, but make sure to catch all errors and display the error message without forcing the script to terminate.