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Thread: Java array

  1. #1
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    Default 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] ;
            }
        }


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    Super Moderator curmudgeon's Avatar
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    Default Re: Java array

    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.

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    Default Re: Java array

    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.

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    Default Re: Java array

    Quote Originally Posted by maple1100 View Post
    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...

  5. The Following User Says Thank You to curmudgeon For This Useful Post:

    maple1100 (February 7th, 2013)

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