Question

I am trying to set the value in an array to a variable. Here is my code:

//init the array as a float
//I have tried to put a value in the brackets, but it returns a different error.
//I initialized it this way so I could call it from other methods
private float[] map;

// generate a "seed" for the array between 0 and 255
float x = generator.nextInt(256);
int n = 1;
// insert into the first 25 slots
while(n <= 25) {
    // here's my problem with this next line
    map[n] = x;
    double y = generator.nextGaussian();
    x = (float)Math.ceil(y);
    n = n + 1;
}

I marked the line with my error, the error returned is: “uncaught exception thrown in…”. What am I doing wrong??? Thanks in advance.

EDIT—–

Here’s the whole exception:

    Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main]

I’m using y to generate a random gaussian, then converting it into a float value and changing x into that float value

I’m pretty sure that It’s that line, because that’s what my compiler told me.

Answer 1

I’m guessing that you get one of two exceptions:

1. You are getting a NullPointerException because have initialized map to null. Assign a non-null value using for example:

   private float[] map = new float[25];
   

2. You are getting an IndexOutOfBoundsException because you are using 1-based indexing instead of 0-based indexing.

Change this:

int n = 1;
while(n <= 25) {
    // etc..
    n = n + 1;
}

To this for loop:

for (int n = 0; n < 25; ++n) {
    // etc..
}