Thread: Java array

Could someone help me figure out why is this giving me a "null error" @ speed[counter] = speedV[counter] ; Thanks

    private double [][] proDistance;
    private double[] speed;
    private double [] speedV;
    private int [] angle;
 
    Catapult(double[] speedCat , int []angleCat)
    {
    speedV= speedCat;
    angle = angleCat;
    proDistance  = new double [speedCat.length][angleCat.length];
    }
 
    public void mphToMps()
    {
        for(int counter = 0 ; counter <  speedV.length;counter++)
        {
            speed[counter] = speedV[counter] ;
        }
    }

Check to see what variable is null on that line. Once you've done this and then looked in your code to see where you've initialized that variable, the problem and solution will become obvious.

Thanks you! Didn't realize I need to set the array size, thought the sped array will just take whatever say the speedV array is.

Originally Posted by maple1100

Thanks you! Didn't realize I need to set the array size, thought the sped array will just take whatever say the speedV array is.

Yep, only if you tell it to do so:

Catapult(double[] speedCat , int []angleCat)
{
    speedV= speedCat;
    speed = new double[speedCat.length];
    // .... etc...