Programming Assignment #5

1. This assignment is comprised of creating a program to read up to (but not more) 25 test grades, then report the number of grades entered; and compute the arithmetic mean (average) and median of the grades. As mentioned, the mean is the arithmetic average and the median is is value in the "middle" of the sorted list. The behavior and layout of this program should be as in the example below. Total points for this assignment will be 99 (33/33/33) points. This assignment is due on or before Tuesday of Finals Week. All objects and techniques necessary for this assignment have been (or will be) covered in class.

2. You should refer to the programming guidelines and follow all guidelines presented there. Failure to adhere to any of the assignment specifications/programming guidelines will result in loss of points.
3. Make sure to keep a copy of the source code that you turn in.
4. Please feel free to ask questions/send e-mail if any items require clarification.

Hints & Updates: (updated Nov 22)

• Pay close attention to the algorithm presented in class. Failure to follow this will most likely result in faulty program execution.
• You should declare an array of double values to store the number of grades. You might want to use a constant for the array size.
• You should assign the return value from the InputDialog method to a variable of type String. Use this variable to determine when the looping control structure should terminate. Refer to the InputDialog link on the syllabus.
• Make sure you follow the instructions for null (pointer) results as discussed in class on the example/handout.
• You will need to use a non fixed, iterative control structure to allow grade input. Termination of this structure will be a result of empty price input (e.g. an empty input OR a cancel). Recall the string.IsEmpty() or string.length() discussion in class. This should be almost identical to program #4's structure.
• To calculate the mean, use a for loop to step through the data, starting at 0 and ending with the number_of_elements - 1.
• Following correct data entry (terminated by OK), the Number of grades, Mean and Median fields should be refreshed.
• You must use a static method for both the mean as well as the median, passing the array to both methods. You will need to pass the actual number of grades entered to both methods also. Array passing looks as follows:

  	invocation: mean = computeMean (grades, numGrades);	// note no brackets
  
  	definition: public static double computeMean (double[] gradeArray, int n)
  

• You should be certain that all invalid data is trapped, as well as too much data (optional). Anticipate what kind of invalid data may be entered. This will require some logical decisions and relational operations.
• Do not hesitate to use the debugging techniques discussed in class (e.g. set a breakpoint at the InputDialog statement) to examine the results of the return values from the InputDialog method.
• To verify/examine your array contents, feel free to include the following method (definition outside of your main, invocation after you filled the array):

  	invocation: arrayDumper (yourArray, numGrades);	// note no brackets
  
  	definition: 
      public static void arrayDumper (double[] anyArray, int numElem) {
          // code to print an array of doubles
          int i;
          for (i = 0 ; i < numElem; i++) {
              System.out.printf("Array[%d]=%6.2f%n", i, anyArray[i]);
          }
      }

• Do the calculateMean method first, making sure it works. for the median, see this page.
• To format the output in the mean and standard deviation, I used:

  	DecimalFormat df = new DecimalFormat("#0.0##");		//indicated 3 places after .
  
  	txtStdDev.setText (df.format (number to format));
  

• Do not hesitate to refer to the Oracle help pages on the syllabus.