Displaying total number of common and uncommon elements between two arrays?

Question

I have two arrays: array testAnswer holds "answers to a exam" and array inputAnswers holds "students answers to the exam".

When i run my code, it displays all the common elements of the two arrays(correct answers), and the uncommon elements (incorrect answers). However, instead of actually displaying the correct/incorrect answers, i want to be able to display the total number of correct/incorrect answers.

My code so far:

private void button1_Click(object sender, EventArgs e)
{
    //Array holding answers to test
    string[] testAnswer = new string[20] { "B", "D", "A", "A", "C", "A", "B", "A", "C", "D", "B", "C", "D", "A", "D", "C", "C", "B", "D", "A" };
    string a = String.Join(", ", testAnswer);

    //Reads text file line by line. Stores in array, each line of the file is an element in the array
    string[] inputAnswer = System.IO.File.ReadAllLines(@"C:\Users\Momo\Desktop\UNI\Software tech\test.txt");

    string b = String.Join(", ", inputAnswer);

    //Increments through array elements in both arrays and checks for matching elements. Displays in listBox.
    for (int i = 0; i < testAnswer.Length; i++)
    {
        if (testAnswer[i] == inputAnswer[i])
            listBox1.Items.Add(inputAnswer[i]); // or testAnswer[i], as appropriate
    }

    //Increments through array elements in both arrays and checks for uncommon elements. Displays in listBox.
    for (int i = 0; i < testAnswer.Length; i++)
    {
        if (testAnswer[i] != inputAnswer[i])
            listBox2.Items.Add(inputAnswer[i]);
    }
}

Answer 1

The following code will provide 2 integers at the end which will hold the answer:

private void button1_Click(object sender, EventArgs e)
{
    string[] testAnswer = new string[20] { "B", "D", "A", "A", "C", "A", "B", "A", "C", "D", "B", "C", "D", "A", "D", "C", "C", "B", "D", "A" };
    string a = String.Join(", ", testAnswer);



    //Reads text file line by line. Stores in array, each line of the file is an element in the array
    string[] inputAnswer = System.IO.File.ReadAllLines(@"C:\Users\Momo\Desktop\UNI\Software tech\test.txt");

    string b = String.Join(", ", inputAnswer);


    //Increments through array elements in both arrays and checks for matching elements. 
    //Displays in listBox.
    for (int i = 0; i < testAnswer.Length; i++)
    {
        if (testAnswer[i] == inputAnswer[i])
            listBox1.Items.Add(inputAnswer[i]); // or testAnswer[i], as appropriate
        else 
            listBox2.Items.Add(inputAnswer[i]);
        }

    int correctAns = listbox1.Items.Count;
    int wringAns = listbox2.Items.Count;
}