How to copy a array into another array that already has data in it?

Question

How would I copy an array say

float arraytobecopied[] = {1.20,2.50,3.60};

to another array that has data in it already say

float newarray[] = {5.20,6.30,4.20};

I want to add the the arraytobecopied to the end of the new array and keep the values in the array. also as a side note this would be an on going process adding to the end of the array every time.

Should i just use a for loop? or is there a better way. (Can't use Array) already tried:(

Answer 1

This question has been asked here before, You can see this page for the answer. How can I concatenate two arrays in Java?

Use System.arraycopy

public static void arraycopy(Object src, int srcPos, Object dest, int destPos, int length)

Answer 2

You can't increase the size of the original array. But you could create a new array, copy both source arrays into it, and assign your reference variable to it.

For example, here's a sketch of a simple implementation. (An alternative is to use System.arraycopy().)

 float[] newerArray = new float[ newarray.length + arraytobecopied.length ];
 for ( int i = 0; i < newarray.length; ++i ) {
     newerArray[i] = newarray[i];
 }
 for ( int i = 0; i < arraytobecopied.length; ++i ) {
     newerArray[ newarray.length + i ] = arraytobecopied[i];
 }
 newarray = newerArray; // Point the reference at the new array

Alternatively, you could use a java.util.ArrayList, which automatically handles growing the internal array. Its toArray() methods make it easy to convert the list to an array when required.