Referencing Namespaces in C# headers with using-directives

Question

I want to have using codes like as shown below, for example:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.IO;

but this c# code below (taken from the question Command prompt output being read as empty string) has no headers like above to compiled with csc.exe in cmd console and i tried to comment on that thread but a requirement of 50 reputation is needed and i had no VB studio IDE yet and im new to learning C#.

var output = new StringBuilder();
var error = new StringBuilder();

cmd.OutputDataReceived += (o, e) => output.Append(e.Data);
cmd.ErrorDataReceived += (o, e) => error.Append(e.Data);

cmd.Start();
cmd.BeginOutputReadLine();
cmd.BeginErrorReadLine();
cmd.WaitForExit();

Answer 1

Process belongs to System.Diagnostics, and StringBuilder belongs to System.Text.

If in doubt, google the method names and see what objects have them on MSDN, then look at their namespace.