Adding to a variable from an Array?

[riiseuk]

Hi there, I'm a bit of a newbie when it comes to C# and only had previous experience with Visual Basic. The problem i'm having revolves around a program I need to create too look at Students marks, the idea is the user inputs the marks and to end the program they press -1.

Now, I have that sorted but the final part requires me to sort grades out by categorising them into A, B, C etc by adding 1 to the grade variable. I have tried If statements but it doesn't seem to work, I can't use "if Marks[count]" because it says it's out of the current context. Here is the code I have so far;

System.Console.WriteLine("\t\t\t\t Student Results Analyser ");
            System.Console.WriteLine("\t\t\t\t ------------------------ ");
            System.Console.WriteLine();

            int[] Marks = new int[100];

            System.Console.Write("Please enter a mark or -1 to finish> ");
            string NumberAsString = System.Console.ReadLine();
            int mark = Convert.ToInt32(NumberAsString);
            int numberOfMarksInput = 0;
            while (mark != -1)
            {
                Marks[numberOfMarksInput] = mark;
                numberOfMarksInput++;
                System.Console.Write("Please enter a mark or -1 to finish> ");
                NumberAsString = System.Console.ReadLine();
                mark = Convert.ToInt32(NumberAsString);
            }

            System.Console.WriteLine();
            System.Console.WriteLine("\t\t\t\t Results ");
            System.Console.WriteLine("\t\t\t\t ------- ");

            
            System.Console.WriteLine();
            System.Console.WriteLine("Total amount of marks entered > {0}", numberOfMarksInput);

            int a = 0;
            int b = 0;
            int c = 0;
            int d = 0;
            int e = 0;
            int f = 0;

Can anyone give me an idea on how I can achieve this? It's completely stumped me.

Thankyou for any help you can give me.

[Singlem]

Think the best way will be to create a void that you send it the mark and it has conditions that will add 1 to the variable while the user input the mark.

public void Grade(int mark)
        {
            if (mark > 80)
            {
                a++
            }
            else if (mark < 79 && mark > 70)
            {
                b++
            }

[riiseuk]

I used a simple if statement at first which was .

if (mark > 80)
{
a = a + 1
}

That worked just once, so maybe I can loop it?

Thanks for the method provided, I tried to incorporate the public void but it just didn't work. Also when I included a++, I was getting the message again "out of the current context".

[james6754]

Hi mate can you give some more info about exactly what your trying to achieve..

you have uneeded parts of code such as

string NumberAsString = System.Console.ReadLine();
            int mark = Convert.ToInt32(NumberAsString);

NumberAsString is in string format anyway so you can do these two lines in a single line...

int mark = convert.toint32(console.readline());

also declare that you are using system at the top so that you do not have to keep writing out System.console.writeline.

using system;

give some more info and will help you..(sorry for the bad punctuation, my fingers are cold.)

[riiseuk]

Cheers for the tips, forgot about using system;

So for the end of the program I want to add numbers to the variables depending on what mark has been input. So for example if 80 is entered it will be logged as "+1" to the "a" variable. I was expecting every mark that was input to trigger a +1 to any of the variables. Then when the user presses -1 a table shows with how many A's, B's, C's...etc

This is basically what I have for the end of the program.

System.Console.WriteLine();
                System.Console.WriteLine("Number of A's > {0}", a);
                System.Console.WriteLine("Number of B's > {0}", b);
                System.Console.WriteLine("Number of C's > {0}", c);
                System.Console.WriteLine("Number of D's > {0}", d);
                System.Console.WriteLine("Number of E's > {0}", e);
                System.Console.WriteLine("Number of F's > {0}", f);

[ddanbe]

Call the Grade function as proposed by Singlem in your while loop.
Declare it as public static void Grade(int mark) etc.
Succes!

[james6754]

Ok well in that case i would probably do something like this..use if statements...

int numberagrade = 0;
int numberbgrade = 0; //so on so on for each grade ..(a,b,c,d,e,f)


console.writeline("enter grade:");
int gradentered = convert.toint32(console.readline()); //gradeentered holds number of grade entered by user.

//now using if statements you can use the ++ operator that will increase number of a variable by one.

if (gradeentered < 0)
{
console.writeline("you have not entered a valid grade");
}
else if (gradentered >= 0 <= 20)
{
numberagrade++;//this will cause numberagrade to increase from 0 to 1
}
else if (gradeentered >=21 <=35)
{
numberbgrade++;//increase bgrade to be increased from 0 to 1
}

so on so on...

once you have done this you can then refer to those variables from you code above...

System.Console.WriteLine();
                System.Console.WriteLine("Number of A's > {0}", a);//change a to numberagrade
                System.Console.WriteLine("Number of B's > {0}", b);//change b to numberbgrade
                System.Console.WriteLine("Number of C's > {0}", c);
                System.Console.WriteLine("Number of D's > {0}", d);
                System.Console.WriteLine("Number of E's > {0}", e);
                System.Console.WriteLine("Number of F's > {0}", f);

does that make sense? let me know

[james6754]

it would be better for you to use functions and properties to set the variables but it doesnt look as though you have got as far as using oop techniques?

[riiseuk]

Right, james I tried it but it was only saving 1 mark and counting the last mark that was entered.

I did however find a solution to it, I thought long and hard about looping the if statement and come up with this.

for (int i = 0; i < numberOfMarksInput; i++)
            {
                if (Marks[i] > 80)
                {
                    a = a + 1;
                }
                else if (Marks[i] > 70 && Marks[i] <= 79)
                {
                    b = b + 1;
                }
                else if (Marks[i] > 60 && Marks[i] <= 69)
                {
                    c = c + 1;
                }
                else if (Marks[i] > 50 && Marks[i] <= 59)
                {
                    d = d + 1;
                }
                else if (Marks[i] > 40 && Marks[i] <= 49)
                {
                    e = e + 1;
                }
                else if (Marks[i] < 40)
                {
                }
}

Thankyou to all that helped, I will stick around on this forum as I am hoping to become a programmer after I graduate (I'm in my first year), and there are some very talented people here. I'll try to contribute whenever I can.

Once again thankyou.

[james6754]

ok mate cool...im in first year at uni too...so just learning..which uni are you at if you dont mind me asking?

[riiseuk]

I'm studying Computer Science at University of Birmingham. What about you?