1) a) b) Consider the following recursive function. You can assume that it will be invoked with non-negative integers. int mystery (int n, { } = m) if (n == return n; int m) else if (n == 0) return m; else if (m == 0) return n; else return mystery(m, n % m); Trace the execution of the three function calls mystery(363, 55), mystery(126, 49), and mystery(81, 37). For each of these three cases, how many calls do each of them make until they return the answer? What are the values of the parameters in each of the calls? Which base case do they reach? What does the mystery function actually do? Can you connect it to a known algorithm for solving this problem?

Mark the following statements as true or false. A double type is an example of a simple data type. (1) A one-dimensional array is an example of a structured data type. (1) The size of an array is determined at compile time. (1,6) Given the declaration: int list[10]; the statement: list[5] - list[3] * list[2]; updates the content of the fifth component of the array list. (2) If an array index goes out of bounds, the program always terminates in an error. (3) The only aggregate operations allowable on int arrays are the increment and decrement operations. (5) Arrays can be passed as parameters to a function either by value or by reference. (6) A function can return a value of type array. (6) In C++, some aggregate operations are allowed for strings. (11,12,13) The declaration: char name [16] = "John K. Miller"; declares name to be an array of 15 characters because the string "John K. Miller" has only 14 characters. (11) The declaration: char str = "Sunny Day"; declares str to be a string of an unspecified length. (11) As parameters, two-dimensional arrays are passed either by value or by reference. (15,16)

(Numerical) a. The following is an extremely useful programming algorithm for rounding a real number to n decimal places: Step 1: Multiply the number by 10n Step 2: Add 0.5 Step 3: Delete the fractional part of the result Step 4: Divide by 10n For example, using this algorithm to round the number 78.374625 to three decimal places yields: Step1:78.374625103=78374.625 Step2:78374.625+0.5=78375.125 Step3:Retainingtheintegerpart=78375Step4:78375dividedby103=78.375 Using this algorithm, write a C++ function that accepts a user-entered value and returns the result rounded to two decimal places. b. Enter, compile, and run the program written for Exercise 11a.

(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?