Method doesn't update variable globally?

Question

So, in the beginning of my java class I define globally:

static long world;

.
Then I have several functions using

world

as an argument. One of theses, called setCell does not work as intended, and I can't figure out why. I have tried error searching with println commands, so now my code looks like this:

public static long setCell(long world, int col, int row, boolean newval){

    if(col>= 0 && col<8 && row>=0 && row<8){

      int bitPosition = col + 8*row;

      long newWorld = PackedLong.set(world, bitPosition, newval);

      System.out.println(newWorld);

      world = newWorld;

      System.out.println(world);

      return world;

    }

    else{

      return world;

    }

}

The main idea of the code is, that it should update

world

by changing one of its bits with the

PackedLong.set

method (which is working well) and then return the new updated

world

.

If we now run:

world =0x20A0600000000000L;

System.out.println(world);

setCell(world, 1, 1, true);

System.out.println(world);

in the main method, we get the following output:

2350984558603665408

2350984558603665920

2350984558603665920

2350984558603665408

From this I have concluded that the commands inside the

setCell

method works as intended, but that the method does not change

world

"globally" through the whole code. How can I solve this issue?
Many Thanks! :)

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Answer 1

You have the parameter world

public static long setCell(long world, int col, int row, boolean newval)

This will hide the global variable and instead update the parameter. You should avoid names the hide other variables that are present in the same scope. Instead choose a different name for the parameter.

Method doesn't update variable globally?

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