Need Help with C# program

Hi I am very new to C#. In an attempt to create a small program that asks the user to input grades and then outputs the grade average, I ran into some issues. This is what I have so far.
I know that it is no where near done, and probably wrong. I would just need to know how to assign the grades A,B,C,D,F and give them values for the calculations. Can anyone help in this matter?

Thanks
Tom

string[] grades = new String[5];



int index = 0;

//loop to have the user input arrays values dynamically
for (index = 0; index <= 4; index++)
{
Console.WriteLine("Enter of your grade " + (index + 1) + ": ");

grades[index] = Console.ReadLine();
}
// loop to print out array values
Console.WriteLine("\nThese are the grades you entered.");
Console.WriteLine("Your Grade average is" index++ / 5);

for (index = 0; index <= 4; index++)
{
Console.WriteLine(grades[index] + "\n");
}



Console.WriteLine("\nPress [Enter] key to exit.");
Console.ReadLine();
}

You should lookup the double.Parse(string s) and double.TryParse(string) functions.
Then you could use a double to add new values and just divide by 5 after the for loop.

Code:

---

int index = 0;
double d = 0;

//loop to have the user input arrays values dynamically
for (index = 0; index <= 4; index++)
{
Console.WriteLine("Enter of your grade " + (index + 1) + ": ");

grades[index] = Console.ReadLine();
d += double.TryParse(...);
}
// loop to print out array values
Console.WriteLine("\nThese are the grades you entered.");
//Console.WriteLine("Your Grade average is" index++ / 5);
Console.WriteLine("Your Grade average is" d / 5);

...

---

Check what would happen if the TryParse fails, what would be added to d?

Hope it helps.

Thank you very much nikel. I am definatley going to try this tomorrow. I decided to let the user enter grades from 0% to 100% as supposed to A, B... If you could give some advice on how to error trap for blank values, letters, and over 100% values to output invalid entry, please try again

Also remember that if:

index = 3

then

index++ / 5 is three fifths

and

++index / 5 is four fifths.

Below is a complete working class in your name TomTom that implements part of the problem statement.

Take time to figure out how I use my variables and their scopes.
Also see that I have used a format specifier {0} in my Console.WriteLine() statements.

Code:

---

using System;
using System.Text;

namespace TomTom1985
{
    class TomTom1985
    {
        public static void Main(string[] args)
        {
            // grades average
            int average = 0;

            // grades are stored as string in this local variables
            string[] grades = new string[5];

            // special characters to exclude in our consoleInput variable
            char[] specialChar = {' ', ','};


            // prompt user to enter grades and read input
            Console.Write("Enter of your grades seperated by commas/spaces: ");
            string consoleInput = Console.ReadLine();// initializing string consoleInpt

            // output a new line
            Console.WriteLine();

            // remove special characters
            grades = RemoveSpecialChars(consoleInput, specialChar);

            // convert grades to int value type
            int[] intGrades = new int[5];

            for (int i = 0; i < grades.Length; i++)
            {
                intGrades[i] = Convert.ToInt32(grades[i]);
            }

            Console.Write("You enterd the following grades: ");

            // loop to print out array values
            for (int index = 0; index < grades.Length; index++)
            {
                Console.Write("{0} ", grades[index]);
            }

            // output a new line
            Console.WriteLine();

            // compute and output average
            average = Average(intGrades);
            Console.WriteLine("Grade Average is: {0}", average);
           
        }

        public static int Average(int[] values )
        {
            // assume total is zero
            int total = 0;

            for (int valuesIndex = 0; valuesIndex < values.Length; valuesIndex++)
            {
                total += values[valuesIndex];
            }


            return total/(values.Length);// return average
        }

        public static string[] RemoveSpecialChars(string input, char[] targets)
        {
            // maximum value to return
            int maxReturn = 5;

            // Split the input string up using the target
            // characters as the delimiters.
            string[] subStrings = input.Split(targets, maxReturn, StringSplitOptions.RemoveEmptyEntries);
            // output will contain the eventual output information.

            return subStrings;
        }
    }
}

---

Try to implement the other possibilities and share with me.
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Lastly I'm learning too... Do continue to share your problems with me as I'd do same to promote our learning. Thanks.