Lab 13: Arrays

Objectives

The objectives of this lab are to become familiar with using arrays in C. Once again we will be using a makefile to build these programs; however, this time you must write the makefile yourself again from scratch (1 Point).

(Hint: the easiest way to do this is to copy a makefile from a previous lab and modify if).

Your makefile should properly compile and link the source files needed to make the three programs described below. The commands we will use to compile your programs are:

          make averages

          make water

Programs

• (4 Points). Exploring Arrays
  • Compile and run the program averages.c. Its input and output was supposed to look like the following.

            10 20 30 30 40 50

            Average of the 6 values read is: 30.000000

            There are 2 values equal to the average.

            The values greater than the average:

            40

            50

            The values less than the average:

            10

            20

• Your task is to fix the output. You will also notice that this program is not well organized (everything is all in a single file) and not well documented (what few comments that are there do not describe the algorithm and do not describe the functions). So in addition to fixing the program, you should break this code up into .c separate source files with related functions together in a file, and provide the appropriate .h files. (Hint: take a look at the second problem and see if any of the functions here can help you there). You should also make sure the code you turn in is well documented with meaningful comments.
• The first thing to fix is to make it compute the average correctly. Hint: This can be done by rewriting the tableAverage function.
• The next thing to fix is to make it determine the number of equal elements correctly. Hint: This can be done by rewriting the tableMatchingElements function.
• After these functions work, it is time to tackle making it print the values greater than or less than equal to the average. The program currently uses tablePrint, but this prints all elements. Hint: A reasonable approach is to make two new functions tablePrintIfLarger and tablePrintIfSmaller that are like tablePrint, except that they only print the appropriate subset of array elements.
• Now that you've got the program working, extend it to print the number of elements greater than the average and less than average, as shown below.

            10 20 30 30 40 50

            Average of the 6 values read is: 30.000000

            There are 2 values equal to the average.

            There are 2 values greater than the average:

            40

            50

            There are 2 values less than the average:

            10

            20

• Hint: It's reasonable to write functions like tableSmallerElements and tableLargerElements that return the number of values smaller or larger than some target value.

• (5 Points). Using Arrays - a tiny project.
  • This problem is a tiny project program. Everything you need is in the directory ~ee160/Code.lect/Water. You will find three .h files ( water.h, meter.h, and reading.h), two .c files ( water.c and reading.c) and one data file, day1. A sample executable is also provided. Your task is to complete this program by writing the function compute_usage() in the file meter.c. The spec for the program is given here. (Hint: think about using functions from the previous problem and the previous labs to save yourself some time).

What You Turn In

Use the "grade" command to turn in the all of the source and data files (.c,.h, and .dat files) and the makefile in your Lab13 directory. Your command will look like the following.

If you are in Section 001 use:

            grade -lab13s1,ee160  *.c *.h makefile

If you are in Section 002 use:

            grade -lab13s2,ee160  *.c *.h makefile

If you are in Section 003 use:

            grade -lab13s3,ee160  *.c *.h makefile

If you are in Section 004 use:

            grade -lab13s4,ee160  *.c *.h makefile

You should verify that you turned in things successfully, which you can do with the command (which simply leaves the file names off from the previous command).

            grade -lab13s1,ee160

            OR

            grade -lab13s2,ee160

            OR

            grade -lab13s3,ee160

NOTE: This is the last of the regular lab assignments. For the remaining weeks of the semester, you should work in the lab with your team on the final project.