Pulsing sequence generator

October 9, 2016 Generator Numbers Sequence

Imagine you need to generate a “pulsing” sequence of numbers which continuously repeats, going up and down between the given values, like this: 5-6-7-8-9-10-9-8-7-6-5-6-7…

Such a sequence may serve different purposes, but in any case, we want a universal solution even for this simple problem. The algorithm is simple too…

class Stairs {
    private int min;
    private int max;
    private int diff;
    private int value;

    public Stairs(int min, int max) {
        this.min = min;
        this.max = max;
        this.diff = max - min;
        this.value = diff - 1;
    }

    public int next() {
        value = (value + 1) % (2 * diff);
        return min + Math.abs(value - diff);
    }
}

Source code and output of the program are available at the end of this post. Moreover, you can try to play with it using the plotter below: change min and max values.

min max

Source code

Example.java

import java.util.*;
import java.lang.*;
import java.io.*;

public class Main {
    public static void main (String[] args) {
        Stairs s = new Stairs(5, 10);

        for (int i = 0; i <= 20; ++i) {
            System.out.println(s.next());
        }
    }
}

class Stairs {
    private int min;
    private int max;
    private int diff;
    private int value;

    public Stairs(int min, int max) {
        this.min = min;
        this.max = max;
        this.diff = max - min;
        this.value = diff - 1;
    }

    public int next() {
        value = (value + 1) % (2 * diff);
        return min + Math.abs(value - diff);
    }
}

Output