VB.Net How to display the frequency distribution of grades from a text file

Question

Evaluate Grades: The file Final.txt contains student grades on a final exam. Write a program that reads the Final.txt file into a string array, converts it into an integer array, calculates the number of grades and the average grade, and then uses loop(s) to calculate and display the percentage of grades that are above average, the standard deviation of the grades, and a frequency distribution showing grades in the following classes: 90-100, 80-89, 70-79, 60-69, and below 60.

I have been able to write the program that reads the text file, calculates the number of grades, the average grade, percentage of grades that are above average, and the standard deviation of the grades. I cannot figure out how to do the frequency distribution showing grades in the classes. Any help is appreciated.

The Grades

Interface

My Code

Answer 1

Your code shows you have created an array of doubles called "grades". Your question said that it should be an array of integers, which would be an easy change to make.

This code should tell you how many grades are in each range:

'This example assumes you have changed your "grades" array to integer

Dim freq90To100, freq80To90, freq70To80, freq60To70, freqBelow60 As Integer

For Each i As Integer In grades

    If i < 60 Then
        freqBelow60 += 1 'this is shorthand for "freqBelow60 = freqBelow60 + 1"
    ElseIf i >= 60 And i < 70 Then
        freq60To70 += 1
    ElseIf i >= 70 And i < 80 Then
        freq70To80 += 1
    ElseIf i >= 80 And i < 90 Then
        freq80To90 += 1
    ElseIf i >= 90 Then
        freq90To100 += 1
    End If

Next

'Change the TextBox names as necessary to match your user interface
txtBelow60.Text = freqBelow60.ToString()
txt60To70.Text = freq60To70.ToString()
txt70To80.Text = freq70To80.ToString()
txt80To90.Text = freq80To90.ToString()
txt90To100.Text = freq90To100.ToString()