Given an integer n and two indexes i, j s.t. i >= j. return a integer where all the bits between positions i and j (both inclusive) are set to 1. The bits outside of this range shall not be modified.

setBetween.java

    /*
    Given an integer n and two indexes i, j s.t. i >= j.
    return a integer where all the bits between positions i and j (both inclusive)
    are set to 1. The bits outside of this range shall not be modified.
    */

    //Comments assuming 8 bit numbers
    //Goal is to make a mask with 1's at positions j through i
    public static int setBetween(int n, int i, int j){ //n = 00010000, i = 3, j = 1

        int left = (1 << i+1) - 1; // 1 << 4 is 00010000, subtract 1 is 00001111
        int right = ~0 << j; //11111111 << 1 is 11111110

        int mask = left & right; //00001110

        return n | mask;
    }