input arr[] = {4,0,2,0,0,6,1,0} output = {4,2,6,1,0,0,0,0} int[] array = { 4,0,2,0,0,6,1,0 }; int nonZeroIndex = 0; //the number of non-zero elements we've seen so far for (int i = 0; i < array.Length; i++) { //skip all zeroes if (array[i] == 0) continue; //put this element to the index we're tracking array[nonZeroIndex] = array[i]; nonZeroIndex++; } //fill the end of the array with zeroes. for (int i = nonZeroIndex; i < array.Length; i++) array[i] = 0; //Console.WriteLine(array); Console.ReadKey();