Here we go!
string str = "My name is Ankush Jassal";
string[] arr = str.Split(' ');
int ix = 0;
int jx = arr.Length - 1;
while (ix < jx)
{
string temp = arr[ix];
arr[ix] = arr[jx];
arr[jx] = temp;
ix++;
jx--;
}
string reversedStr = string.Join(" ", arr);
Console.WriteLine(reversedStr);