using System;

public class Program

{

    public static void Main()

    {

        char []array1= new char[] {'a','b','c'};

        char []array2= new char[] {'1','2','3','4'};

        ConcatenatArray( array1 , array2);

    }

    public static void  ConcatenatArray(char []ar1, char []ar2  )

    {

        int l1 = ar1.Length,  l2 = ar2.Length ;

        char []resArray = new char[100];

        int a=0,b = 0,c = 0;

        while(a<l1 &&b<l2)

        {

        resArray[c++ ] = ar1[a++];

        resArray[c++ ] = ar2[b++];  

        }

        while(a<l1)

        {

        resArray[c++ ] = ar1[a++];

        }

        while(b<l2)

        {

        resArray[c++ ] = ar2[b++];  

        }

        for(int i=0;i<l1+l2;i++)

        {

        Console.Write(resArray[i]+",");

        }

    }

}

​

​