Question

Say I have an array of 10 elements. Another part of my program determines I must remove the item at index 4.

What is the most efficient method to remove the item and shorten the array?

I wrote the following method, however it does not seem to work properly. Am I missing something, for example if the index to remove is 0? The method is called by sending an array and the index to be removed.

I realize there are Array Lists and other types of lists. However this is an assignment for a programming course and MUST use ARRAYs.

//Removes the index from the array and returns the array.
    NumberTile[] removeAndTrim(NumberTile[] array, int index){
        NumberTile[] save = array;
        array = new NumberTile[save.length-1];
        for (int i=0; i<index; i++){
            array[i]=save[i];
        }//end for loop
        for (int j=index; j<save.length-1; j++){
            array[j]=save[(j+1)];
        }
        return array;
    }//end removeAndTrim

Answer 1

public NumberTile[] removeAndTrim(NumberTile[] a, int index){
    NumberTile[] result = new NumberTile[a.length-1];
    for (int i = 0; i < result.length; i++){
       result[i] = a[((i < index) ? i : i + 1)];
    }
    return result;
}

Your most efficient way would be one loop / traversal and one array creation.
(Without using arraycopy that is).

Note: This doesn’t alter the values of the parameter array at all, just returns a new one.