CMPS 221 - Homework 5

Homework 5 - File I/O and Arrays: Part 2

Due: Wednesday October 27, 2010 at 5:00pm
NOTE: No late assignments will be taken after Saturday October 30, so the solutions can be posted to study before Midterm 2.

Name your file hw5.cpp and email it to my account.

Modify the class menu program to work on an array as follows. The menu will print this to the screen:

  Welcome to the CS221 Homework 5 Menu
  ===============================================
  1.  Enter a list of integers from the keyboard.
  2.  Read a list of integers from a file.
  3.  Multiply all integers in the list.
  4.  Calculate the average and standard deviation
      for all the integers in the list.

  0.  Exit
  ===============================================
  Enter selection:

The list read in by either option 1 or 2 should be saved in an array. Use this saved array to do options 3 and 4. Options 3 and 4 should print out an error if they are selected before input is given (via option 1 or 2).

Options 3 and 4 should use a calculation function (e.g. calc_product, calc_average, calc_deviation) that takes an array and the size of the array and returns the appropriate calculation. Recall from Homework 4 that the standard deviation calculates the sum squared error (sse) then divides by the size - 1, then takes the square root.

Required elements:

The same array variable will be used for all options. Declare this array in main's scope and pass it as an array parameter to the functions.
If option 1 and 2 are selected one after the other, throw away the data from the earlier option. In other words, input beginning at index 0.
Option 2 MUST prompt the user for a filename, read the user's response into a filename variable and then open the input stream for that particular filename. Points will be deducted if a hard-coded filename, such as fin.open("hw5_input1"), is used.
If size is less than 0 when option 3 is selected, issue an error message about needing to input the array from option 1 or 2.
If size is less than 2 when option 4 is selected, issue an error message saying that the standard deviation cannot be calculated for less than 2 elements.
The array calculation functions will be pure calculation functions. They will NOT cout the result, but will instead return the result. The calling function is responsible for storing and printing the result.

You may opt to use additional functions to support your menu, such as input functions for options 1 and 2 or a menu function to print the menu. These are not required for the assignment, but should you opt to use them, they should be syntactically and logically correct.

Use the following files as input to option 2: hw5_input1 hw5_input2