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Copying Arrays

When you copy an array variable, remember that you are copying a reference to the array. For example:

    double[] a = new double [3];
    double[] b = a;

This code creates one array of three doubles, and sets two different variables to refer to it. This situation is a form of aliasing.

Any changes in either array will be reflected in the other. This is not usually the behavior you want; instead, you should make a copy of the array, by allocating a new array and copying each element from one to the other.

    double[] b = new double [3];

    int i = 0;
    while (i < 4) {
      b[i] = a[i];
      i++;
    }

Home Arrays Copying Arrays

Last Update: 2011-01-24