How do I use arraycopy?

Grimtin10

So, i'm trying to get the differences between two boolean arrays, (I have a setter, i'm trying to make a screen) but if I change one, it changes the other.

kfrajer

Please provide your code.

Kf

Chrisir

To make them different you cant say

array1=array2

Instead use arraycopy

https://www.tutorialspoint.com/java/lang/system_arraycopy.htm

Grimtin10

But i did

Grimtin10

i mean i used arraycopy

Grimtin10

public void updateScreen(boolean[][] s){ arrayCopy(s,screen); }

Chrisir

Too short

Can you provide an entire sketch demonstrating the issue

Here you copy s into screen....

quark

A 2D array is an 'array of arrays' so when you use arrayCopy(s,screen); you are copying the array references from s to screen.

This means that screen[0] is the same array as s[0] so when you use

s[0][5] = true;

you are also setting screen[0][5] to true and visa-versa.

Assuming that s and screen have both been created and have the same dimensions then this will copy the individual elements

public void updateScreen(boolean[][] s) {
  for (int idx = 0; idx < s.length; idx++) {
    arrayCopy(s[idx], screen[idx]);
  }
}

Grimtin10

ohhhhhhhhhhhhhhh