[Solved] CNIT155 Assignment-11

Objectives:

• Checkbox control
• Saving to the text file
• Reading from a text file
• Form Closing Event Method
• Form_Load event method

Problem Description: Design a C# project to store up to 100 students’ information in parallel arrays. The user will enter each student’s name, score in provided Textboxes and check the Checkbox if student is a CIT major, followed by a click on the Enter button to store the student in the parallel arrays.

Figure 1 – Screen capture when Display is clicked

Class Scope Declarations:

• Declare a named constant to store size of the parallel arrays = 100.
• Declare 3 parallel arrays to store up to 100 students’ names, scores and CIT major (true / false). Use the named constant at declaration.
• Declare a counter to keep track of the next available index in the array.
• Declare a variable to store the file name with the full path:

Private String mFileName = Path.Combine (Application.StartupPath , “Students.txt”);

Enter Button (pseudo-code)

• Validate the user’s input – Call the helper method.
• If data is not valid – return.
• Store the entered data in parallel arrays.
  • If the check box is checked, store true in the array, otherwise store false.
• If array is full
  • Inform the user
  • Disable the Enter button.
• Call the helper method to clear the input.

Display Button:

• Inform the user if array is empty, and return.
• Display all the names, scores and CIT major (true / false) in the Listbox.

Stats Button:

• Inform the user if array is empty, and return.
• Clear the Listbox
• Display number of students entered.
• Display number of CIT students entered.
• Compute the average. Display it with proper format.

Clear Button:

• Call ClearInput() to clear the entered input.
• Clear the Listbox.

Exit Button: End program execution.

FormClosing Event:

Save data stored in parallel arrays to a text file named students.txt, one student per line, with tab delimited fields. Refer to Figure-3.

• Declare an object variable of type StreamWriter.
• Open the file txt at the same location as your project’s .exe
• Write a loop to write each student’s data on a separate line, tab delimited.
• Close the file.

Helper Methods:

• ValidateInput():
  1. Input: none
  2. Output data type: bool
  3. Task: Validate user’s input based on the following rules:

– Existence check on name.

– Score must be a whole number.

– Valid range for score is 0 to 100, both inclusive.

• ClearInput ( )
  1. Input: none
  2. Output: void
  3. Task: Clear the entered data and set the focus to the top textbox.

Call this method at the end of the Enter button and from the Clear button.

• DisplayMessage( )

1. Input: String
2. Output data type: void
3. Task: Display the input string using MessageBox.Show(). The Messagebox should include all 4 arguments.

FormClosing Event Method

Save content of the parallel arrays to the text file in this event procedure.

• Confirm with the user whether to end the program execution or not.
  • Use MessageBox.Show to ask this question. Provide buttons Yes and No in the Messagebox plus the Question icon.
  • If the user’s answer is NO,
    • Cancel the closing event.
  • Save data stored in parallel arrays to a text file.
    • Declare an object variable of StreamWriter Open the file (use class scope filename) to write to.
    • Write a loop to write each student’s data to the file in a tab delimited format.
    • Close the file.
  • Include Exception Handling code to handle exceptions (try – catch – finally).

Figure 22 – An image of the text file

Form_Load Event Method

Upload / read data from a text file into the program in parallel arrays in this event method.

• Check if the file exists (Use the class scope filename).
  • If file does not exist, return.
• Declare an Object variable of StreamReader class and open the file mFilename for reading.
• Declare a string variable to store a line read from the file.
• Write a loop to read until end of the file.
  • Read a line into the string variable.
  • Split the line to extract pieces of data.
  • Store pieces of data in parallel arrays at mIndex. –
• Close the file.
• Include Exception Handling code to handle exceptions (try – catch – finally).