Making an C IDE ,How can execute a program that takes user inputs , Standrard Input /Output

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C#

.NET

I am trying a make C IDE (Integrated Development Environment ) using C#.Net in Windows 7. So I need Compile and executed C program and Display output and Error Messages in textbox or Label

Displaying output and Error Messages can easily done

pp.RedirectStandardOutput = true;
            pp.UseShellExecute = false;
            pp.CreateNoWindow = true;
            pp.RedirectStandardError = true;
            Process p = new Process();
            p.StartInfo = pp;
            p.Start();

            StreamReader sr = new StreamReader(p.StandardOutput.BaseStream, p.StandardOutput.CurrentEncoding);
            string line = "";
            string output = "";

            while ((line = sr.ReadLine()) != null)
            {
                output += line;
            }
            p.WaitForExit();
            p.WaitForExit();

            textBox1.Text = output;

but how can i execute a program that takes inputs from user programs like this

void main()
{
int a;
printf("/nEnter a Number");
scanf("%d",&a);
printf("Number is  %d",a);
}

and display output or error Messages in a textbox or label?

i tried StandradInput

p.StandardInput.WriteLine("7");

but its doesn't work for me.