3. Make a program that finds sum of all diagonal elements of an array with the size of [3,3].

(Numerical) Given a one-dimensional array of integer numbers, write and test a function that displays the array elements in reverse order.

(Statistics) a. Write a C++ program that reads a list of double-precision grades from the keyboard into an array named grade. The grades are to be counted as they’re read, and entry is to be terminated when a negative value has been entered. After all grades have been input, your program should find and display the sum and average of the grades. The grades should then be listed with an asterisk (*) placed in front of each grade that’s below the average. b. Extend the program written for Exercise 1a to display each grade and its letter equivalent, using the following scale: Between90and100=AGreaterthanorequalto80andlessthan90=BGreaterthanorequalto70andlessthan80=CGreaterthanorequalto60andlessthan70=DLessthan60=F

(Electrical eng.) a. An engineer has constructed a two-dimensional array of real numbers with three rows and five columns. This array currently contains test voltages of an amplifier. Write a C++ program that interactively inputs 15 array values, and then determines the total number of voltages in these ranges: less than 60, greater than or equal to 60 and less than 70, greater than or equal to 70 and less than 80, greater than or equal to 80 and less than 90, and greater than or equal to 90. b. Entering 15 voltages each time the program written for Exercise 7a runs is cumbersome. What method could be used for initializing the array during the testing phase? c. How might the program you wrote for Exercise 7a be modified to include the case of no voltage being present? That is, what voltage could be used to indicate an invalid voltage, and how would your program have to be modified to exclude counting such a voltage?