CODEWITHSUNDEEP
c#visual-studio
CoreyC
CoreyC

Reputation: 35

writing program using arrays and averages in C#

I am writing a program using GUI in C# that includes three text boxes (one for name input, one for grade input and one for grade output), and five buttons (one to take in the name/grade and add to corresponding arrays, one to display just the name and grade that were just entered, one to display lowest grade, one to display highest grade and one to display the class average).

I have the form designed but need help with some of the code, there are two arrays one for the grade and one for name both which have five values initially stored within them. Here is the code I have so far:

    namespace WindowsFormsApplication3
{
using static System.Console;
public partial class highestGrade : Form
{
    int[] grade = new int[] { 90, 80, 60, 70, 80, };
    string[] name = new string[] { "Sally", "Joe", "Sue", "Pete", "Tom", };
    double sum = 0;
    double average;
    int x = 4;
    int y = 4;
    int z = 0;
    public highestGrade()
    {
        InitializeComponent();
    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    private void label2_Click(object sender, EventArgs e)
    {

    }

    private void addStudent_Click(object sender, EventArgs e)
    {
        if (x <= 9)
        {
            Array.Sort(grade, name);
            name[x] = textBox1.Text;
            grade[x] = Convert.ToInt32(textBox2.Text);
            sum = sum + grade[x];
            textBox1.Text = string.Empty;
            textBox2.Text = string.Empty;
        }


    }

    private void display_Click(object sender, EventArgs e)
    {
        outputText.Visible = true;
        outputText.Text = textBox1.Text + "   " + textBox2.Text;
    }

    private void lowestGrade_Click(object sender, EventArgs e)
    {
        Array.Sort(grade, name);
        outputText.Visible = true;
        outputText.Text = name[z] + "  " + grade[z];
    }

    private void button4_Click(object sender, EventArgs e)
    {

        Array.Sort(grade, name);
        outputText.Visible = true;
        outputText.Text = name[y] + "  " + grade[y];

    }

    private void averageGrade_Click(object sender, EventArgs e)
    {

        for (int y = 0; y < 5; y++)
        {
            sum = sum + grade[y];
        }
        average = sum / grade.Length;
        string avgOutput = Convert.ToString(average);
        outputText.Visible = true;
        outputText.Text = "Class Average:   " + avgOutput;
        y++;
        }

}
}

I need the program to take input for grade/name up to 10 students, while being able to output the lowest/highest grade continually whenever the user clicks. It also needs to output the total average continuously whenever the user clicks.

The average is not calculating correctly, it keeps adding to the sum for each time the average button is clicked and I cannot get the highest grade to hold its value. For example: if i enter a new grade as 100 then click highest grade, it displays that grade which is what I want. But for the next grade if i enter 95, it replaces the 100 with the 95.

Any help would be appreciated thank you.

Upvotes: 0

Views: 1191

Answers (1)

Georg Patscheider
Georg Patscheider

Reputation: 9463

You have to reset the current sum before adding the grades again to calculate the average correctly:

private void averageGrade_Click(object sender, EventArgs e) {

    sum = 0; // reset sum

    for (int y = 0; y < 5; y++) {
        sum = sum + grade[y];
    }
    average = sum / grade.Length;
    string avgOutput = Convert.ToString(average);
    outputText.Visible = true;
    outputText.Text = "Class Average:   " + avgOutput;
}

You can also use LINQ to calculate sums and averages, no need to write for loops:

using System.Linq;
var sum = grade.Sum();
var average = grade.Average();

As for the problem with lowest/highest grade: calculate these every time the button is clicked. Eliminate the global variables y, z.

private void lowestGrade_Click(object sender, EventArgs e) {
    // this probably only needs to be sorted if a value is added or removed (addStudent_Click)           
     Array.Sort(grade, name); 
     outputText.Visible = true;

     // first element (with index 0) will be the lowest because arrays are sorted now
     outputText.Text = name[0] + "  " + grade[0]; 
 }

You can also use LINQ .First() and .Last() to access the first or last element of a collection or without the need of sorting use LINQ .Min() and .Max() methods.

Upvotes: 2

Related Questions