the = in setup won't work

the reason is that  the = as you have it doesn't do a copy but sets both arrays on the same adress in memory (pointers to the same array there)

Merci !!!
it does work

great!

little adding question:
For my project, the array.length is 25, so I would like to organise it to see in a clever way  changes.
I try to make println operation- I would like changes to be in one block in console.
But I can't figure how to deal with the prinln operation in my loop !
here's the code I have:
(hope I'm clear)

1. //mousePressed modify the source array, and it should println the changed element…but walou…
   
   int[] source=new int[25];
   int track_source[] = new int[25];
   void setup()
   {
     size(300, 300);
     for (int i=0;i<25; i++)
     {
       track_source[i] = source[i];
     }
     //  track_source= source;
     frameRate(1);
   }
   
   void draw()
   {
   
     background(200);
     hasard();
     for (int i  =0; i<25; i++)
     {
       if (track_source[i]  !=source[i] )
       {
         println("source["+i+"]= "+source[i]);
   
         track_source[i] =source[i] ;
         if (i==24) {
           println("-----------");
           println("NEW CHANGES===");  //WORKS AS EXPECTED IF NUMBER OF CHANGES IS i-1 }
         }
       }
     }
   }
   void hasard()
   {
   
     for (int i =0; i<25; i++)
     {
       source[i] = int(random(2)); // CANT PUT PRINT HERE- IT IS JUST TO DEMONSTRATE
     }
   }
   
   

i am on a journey and can't test it.