Accepting and Returning Arrays in Java

This section will explain the code listed in the previous section.  Let us start with the following:

    int[] a;

The above defines a variable “a” as an array of type “int” (or integer).  Further proceeding, we have the following:

    public void setValues(int[] p)    {
        a = p;
    }

The above method (setValues) simply accepts an integer array referred by “p.”  We simply copy all the values available in “p” to “a” by assigning directly to it.  Further proceeding we have the following:

    public int getSum() {
        int s=0;
        for(int i=0;i<a.length;i++) {
            s += a[i];
        }
        return s;
    }

The above method simply iterates through each and every element present in the array “a” and sums all those values into “s,” which is finally returned back to the calling program.

Now, if we proceed to our “test” frame, we have the following initially:

        MyCalc obj1 = new MyCalc();
        int[] ar = {12,23,34,45,56,67};

I instantiated an object called “obj1” in the first statement. The second line simply creates an array named “ar” with a few values to be stored inside it. Further proceeding, we have the following:

        obj1.setValues(ar);

The above statement simply calls the method “setValues” by passing the array “ar” to “p.”  We finally display the sum using the following:

        int r;
        r = obj1.getSum();
        this.lblMsg.setText("Sum = " + String.valueOf(r));