Programming Exercise 1: Malloc up a Two-Dimensional Array
The purpose of the program is for you to practice referencing a two-dimensional array, but the space for that two-dimensional array was created at run-time via a call to malloc. Realize that C’s [ ] operator (index or subscript operator) cannot be used in a double subscripting context unless you do a work-around. In this problem you will malloc up enough space to hold r × c integer values via a single call to malloc where r is the number of rows and c represents the number of columns:
malloc ( r * c * sizeof (int) ) ;

You should read in the values of r and c via the keyboard using scanf.
In this problem, I am not asking you to create r pointers to integers. I am asking you to create space to hold r × c integers – all of which are consecutively laid out in memory. You need to visualize this.

I want you to then fill the space. For this purpose, you need to use a nested for loop to fill the array. Each cell should be assigned the number i + j. Thus, you need to keep track of your own offset via i*c + j within a single subscript. After you have done this, you should walk the entire array and then add up each element to form the sum. You should output the sum.

I want you to discover that you can use a single [ ], but you must manipulate your own indices. I do not want you to use a [ ][ ]. In fact, with a single call to malloc you cannot. Remember, when you compile your code you should not have any warnings.

Programming Exercise 2: Simply Two Dimensional
The purpose of this exercise is to use the two-subscript method of dynamic memory allocation. Input for this program is a two-dimensional array of floating point data located in a file named testdata2. The input array will contain 3 rows of data with each row containing 5 columns of data. Thus, if the input values are:
4.33 5.33 1.11 99.00 100.00
1.0 33.3 12.5 1.1 -1000.00
22.1 11.9 2.4 8.3 8.9

Use malloc to create an array that holds pointers. Each element of that array points at another array, which is the row of data. Use malloc in a loop to create your rows. Then you can use two subscript operators [r][c] to get at your data in order to sum the elements in a row and calculate the average, and to sum the elements in a column and calculate the average.
Your program should output:

The average values for the three rows are: 41.95 -190.42 10.72
The average values for the five columns are: 9.14 16.84 5.34 36.13 -297.03

This program calls for hard-coded height and width of the two-dimensional array, known ahead of time (3 × 5). Instead of writing in the literal numbers in your code, create two global constant variables to hold those dimensions, and use those variables in your code.

Programming Exercise 3: Non-recursive (Iterative) Persistence of a Number
Multiplying the digits of an integer and continuing the process gives the surprising result that the sequence of products always arrives at a single digit number. For example,
715 ---- 35 ---- 15 ---- 5 27 ---- 14 ---- 4
4000 ---- 0
9

The number of times products need to be calculated to reach a single digit is called the persistence number of that integer. Thus, the persistence number of 715 is 3, the persistence number of 27 is 2, the persistence number of 4000 is 1, and the persistence number of 9 is 0. You are to write a program that will continually prompt the user to enter a positive integer until EOF has been entered via the keyboard. For each number entered, your program should call a persistence function. The result from calling persistence should be displayed to the user.

Programming Exercise 4: Recursive Persistence of a Number
Redo the previous programming exercise (assignment09pe03) except make it a recursive solution. Your recursive persistence function should have only a single argument. Re-use the same main function implemented in the previous programming exercise.

Programming Exercise 1: Malloc up a Two-Dimensional Array The purp...