How to read from input and output to output in C#?

Question

C++ / C#

What should the input from input.txt look like, and the output to output.txt, when solving Olympiad problems?

Answer 1

using System;
using System.IO;

namespace InputOutputExample
{
    class Program
    {
        static void Main(string[] args)
        {
            string inputFile = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "input.txt");
            string outputFile = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "output.txt");

            using var input = new StreamReader(File.OpenRead(inputFile));
            Console.SetIn(input);
            
            using var output = new StreamWriter(File.OpenWrite(outputFile));
            Console.SetOut(output);

            string line = null;
            while ((line = Console.ReadLine()) != null)
            {
                Console.WriteLine(line);
            }
        }
    }
}