using System;
using System.Text;

public class Test
{
	public static void Main()
	{
		char[] true_false = new char[2]{'V','F'};  
		Random rand = new Random();
		var generate_code = new StringBuilder();
		int lenght_of = 5;

		for(int i =0; i < 10;i++) { 
			generate_code.Append(generateCodeWithLength(rand, true_false, lenght_of));
    		Console.WriteLine(generate_code); 
    		generate_code.Remove(0, generate_code.Length);
		} //Output expected: "FF" "VV" "FV" "VF" "FF"
	}
	
	public static string generateCodeWithLength(Random rand, char[] true_false, int length) {
    	var result = new StringBuilder(length);

    	for (var i = 0; i < length; i++) {
        	result.Append(true_false[rand.Next(0, 2)]);
    	}

    	return result.ToString();
	}
}