using System;

using static System.Console;

using System.Diagnostics;

using System.Text;

​

public class Program {

    const int Limit = 1000;

    static int[] dataInt = new int[Limit];

    static string[] dataString = new string[Limit];

​

    public static void Main() {

        for (int i = 0; i < Limit; i++) {

            dataInt[i] = i;

            dataString[i] = i.ToString();

        }

        Time(ConcatenationInt);

        Time(JunctionInt);

        Time(BuilderInt);

        Time(AdditionInt);

        Time(ConcatenationString);

        Time(JunctionString);

        Time(BuilderString);

        Time(AdditionString);

    }

​

    static void Time(Func<int> action) {

        var sw = Stopwatch.StartNew();

        int result = action();

        sw.Stop();

        WriteLine($"{result} - {sw.ElapsedTicks:000,000,000} - {action.Method.Name}");

        GC.Collect();

        GC.WaitForPendingFinalizers();

    }

​

    static int AdditionInt() {

        var tmp = "";

        for (int i = 0; i < Limit; i++) tmp += dataInt[i];

        return tmp.Length;            

    }

​

    static int AdditionString() {

        var tmp = "";

        for (int i = 0; i < Limit; i++) tmp += dataString[i];

        return tmp.Length;            

    }

​

    static int ConcatenationInt() => string.Concat(dataInt).Length;            

​

    static int ConcatenationString() => string.Concat(dataString).Length;            

​

    static int JunctionInt() => string.Join("", dataInt).Length;            

​

    static int JunctionString() => string.Join("", dataString).Length;            

​

    static int BuilderInt() {

        var tmp = new StringBuilder();

        for (int i = 0; i < Limit; i++) tmp.Append(dataInt[i]);

        return tmp.Length;            

    }

​

    static int BuilderString() {

        var tmp = new StringBuilder();

        for (int i = 0; i < Limit; i++) tmp.Append(dataString[i]);

        return tmp.Length;            

    }

}