using System;

public class Program

{

    public static void Main()

    {

        // We should declare and initialize length before the for loop

        int length = 3;

        for (int offset = 0, c1, c2; offset < length; ) 

        {

            // we should initialize c1 and c2 within the loop

            c1 = 5;

            c2 = 7;

            // since for loop has empty iteration, we should provide it somewhere here 

            offset += 1;

            Console.WriteLine($"{offset} {c1 + c2}");

        }

    }

}