sumcalculator.java

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import java.io.*;

/**
 * This class obtains the sum of the integers in a specified range.
 *
 * @author  author name
 * @version  1.0.0
 */
public class SumCalculator  {

    private static BufferedReader  stdIn =
        new BufferedReader(new  InputStreamReader(System.in));

    private static PrintWriter  stdOut =
        new PrintWriter(System.out, true);

    private static PrintWriter  stdErr =
        new PrintWriter(System.err, true);

    /**
     * Sums integers in the range <code>lower..upper</code>.
     *
     * @param lower  the lower limit.
     * @param upper  the upper limit.
     * @return  the sum of the integers in the range
     *          <code>lower..upper</code>.
     */
    public static int  sumRange(int lower, int upper)  {

        stdErr.println("  sumRange called.  lower:" + lower +
                       "  upper:"  + upper);

        int  total = 0;

        for (int i = lower ; i <= upper; i++) {
            total += i;
            stdErr.println("    for loop,  i:" + i + "  total:" +
                           total);
        }

        return total;
    }

    /**
     * display the sum of integers in a specified range.
     *
     * @param args  not used.
     */
    public static void  main(String[] args)  {

        int lower;
        int upper;

        try  {
            stdErr.print("lower limit:  ");
            stdErr.flush();
            lower = Integer.parseInt(stdIn.readLine());
            stdErr.print("upper limit:  ");
            stdErr.flush();
            upper = Integer.parseInt(stdIn.readLine());
            stdOut.println("The result is: " + sumRange(lower, upper));
        } catch (NumberFormatException  nfe)  {
            stdErr.println(nfe.toString());
        } catch (IOException  ioe)  {
            stdErr.println(ioe.toString());
        }

    }
}