import java.lang.reflect.*;

/**
 * An example that illustrates the determination of the interval
 * that contains a value.
 *
 * @author  Prof. David Bernstein, James Madison University
 * @version 1.0
 */
public class IntervalMembership {

    /**
     * The entry point of the application.
     *
     * @param args  The command line arguments
     */
    public static void main(String[] args) {
        
//[taxBracket
        int[] single = {0, 9326, 37951, 91901, 191651, 416701, 418401};

        int bracket;
        bracket = indexOf(125350, single);
//]taxBracket
        
//[taxRate
        double[] rate = {-1.0, 10.0, 15.0, 25.0, 28.0, 33.0, 35.0, 39.6};

        double marginal;
        marginal = rate[bracket]; 
//]taxRate


//[grades
        int[] intervals = {
            0, 60, 63, 67, 70, 73, 77, 80, 83, 87, 90, 93};

        double[] gp = {
            -1.0, 0.0, 0.7, 1.0, 1.3, 1.7, 2.0, 2.3, 2.7, 3.0, 3.3, 3.7, 4.0};

        String[] letter = {
            "NA","F","D-","D","D+","C-","C","C+","B-","B","B+","A-","A"};

        int i;
        String out;
        
        i = indexOf(88, intervals);
        out = String.format("Grade: %s (%3.1f)", letter[i], gp[i]);
//]grades
    }
    


//[indexOf
    /**
     * Determine which interval, defined by an array of boundaries,
     * contains a particular value. The intervals are formed from
     * the boundaries as follows:
     *
     *          Interval                     Index
     *
     * [-Infinity,      boundary[0])           0
     * [ boundary[0],   boundary[1])           1
     * [ boundary[1],   boundary[2])           2
     *                .                        .
     * [ boundary[n-2], boundary[n-1])        n-1
     * [ boundary[n-1], Infinity)              n
     *
     *
     * @param value     The value of interest
     * @param boundary  The array of boundaries that define the intervals
     * @return          The index of the interval containing the value
     */
    public static int indexOf(int value, int[] boundary) {
        int      i, n;
       
        n = Array.getLength(boundary);
       
        i = 0;
        while ((i < n) && (value >= boundary[i]))  ++i;          
       
        return i;       
    }
//]indexOf


//[taxes
    /**
     * Determine the U.S. (marginal) income tax rate for a single
     * person in 2017.
     *
     * @param income  The person's income
     * @return The tax rate
     */
    public static double taxRate(int income) {
        int[] single  = {0, 9326, 37951, 91901, 191651, 416701, 418401};
        double[] rate = {-1.0, 10.0, 15.0, 25.0, 28.0, 33.0, 35.0, 39.6};

        return rate[indexOf(income, single)];
    }    
//]taxes

}