Java: Generate a sequence of numbers within a range?

Question

I need to be able to generate a series of ascending or descending numbers within a range.

public int nextInRange(int last, int min, int max, int delta, boolean descending) {
        delta *= descending ? -1 : 1;

        int result = last + delta;
        result %= max;
        return Math.max(result, min);
}

This works fine for ascending values, but not descending values. I've been staring at this for a while, and I'm not sure how to make it work for descending values. Any ideas?

create a loop that starts at your min value and ends on your max, and vice versa for descending — Trevor Arjeski
– Trevor Arjeski, Commented Apr 16, 2011 at 19:44
I'm not entirely sure what the properties of the series are supposed to be, but in any case, the descending parameter seems redundant, since the caller could simply provide a negative value for delta which would be equally intuitive. Also, mixing the two schemes for restraining into the range (modulo for the top range, clamp at the bottom range) seems odd too. — Jim Blackler
– Jim Blackler, Commented Apr 16, 2011 at 19:54

QuantumMechanic · Accepted Answer · 2011-04-16 20:03:48Z

1

How about this, where delta is negative when you want a descending sequence?

public int nextInRange(int last, int min, int max, int delta) {
    int result = last + delta;

    // now clip to min and max
    if (result > max) {
        result = max;
    } else if (result < min) {
        result = min;
    }

    return result;
}

or perhaps less straightforwardly, have the body of the function be the single line:

return Math.min(max, Math.max(last + delta, min));

edited Apr 16, 2011 at 20:03

answered Apr 16, 2011 at 19:58

QuantumMechanic

14k4 gold badges47 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Java: Generate a sequence of numbers within a range?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related