What do macOS and Windows use to prevent us from accidentally deleting files?

Write a program that uses a widgetviewer object to do the following: generate two random integers between 1 and 9 (inclusive). name one of them x, the other y. display them to the user using jlabel objects. create a jlabel object displaying the text "enter an operation number." create a jtextfield for the user's input. create a jbutton displaying the text "press here when you've entered your operation." use addandwait to add it to the widgetviewer object. when the user clicks the jbutton, evaluate operation in the following order to determine the one and only mathematical operation to perform on x and y. use a jlabel to display the result. if operation is between 1 and 10 inclusive, add x and y. if operation is evenly divisible by 4, subtract y from x. if operation is evenly divisible by 5, use integer division to divide y into x. if operation is an even number, use floating point division to divide y into x. if none of the other tests on operation apply, multiply x and y. note: operation can be negative or zero.

One of your customers wants you to build a personal server that he can use in his home. one of his concerns is making sure he has at least one backup of their data stored on the server in the event that a disk fails. you have decided to back up his data using raid. since this server is for personal use only, the customer wants to keep costs down. therefore, he would like to keep the number of drives to a minimum. which of the following raid systems would best meet the customer's specifications? a. raid 0 b. raid 1 c. raid 5 d. raid 10

Write a program that uses a random number generator to generate a two digit positive integer and allows the user to perform one or more of the following operations: a. double the number. b. reverse the digits of the number. c. raise the number to the power of 2, 3, or 4. d. sum the digits of the number. e. if the number is a two-digit number, then raise the first digit to the power of the second digit. f. if the number is a three-digit number and the last digit is less than or equal to 4, then raise the first two digits to the power of the last digit. after performing an operation if the number is less than 10, add 10 to the number. also, after each operation determine if the number is prime. each successive operation should be performed on the number generated by the last operation. your program should not contain any global variables and each of these operations must be implemented by a separate function. also, your program should be menu driven. 7. (fraction calculator) write a program that