/**
 * Write a program to produce the sum of 1, 2, 3, ..., to an upperbound (e.g., 100).
 * Also compute and display the average. The output shall look like:
 * <code>
 *      The sum is 5050
 *      The average is 50.5
 * </code>
 */

package javaexercises.flowcontrol;

/**
 *
 * @author User
 */
public class SumAndAverage {
    
    /**
     * 
     * @param args 
     */
    public static void main(String[] args)
    {
        int upperBoundNumber = 100;
        
        if (upperBoundNumber <= 0) {
            System.out.println("Error: upperbound less than 0!");
            return;
        }
        
        SumAndAverage aSumAndAverage = new SumAndAverage();
        aSumAndAverage.printSumNumbersUsingForLoop(upperBoundNumber);
        aSumAndAverage.printSumNumbersUsingDoWhileLoop(upperBoundNumber);
        aSumAndAverage.printSumNumbersUsingWhileDoLoop(upperBoundNumber);
        aSumAndAverage.printSumNumbersFromRange(111, 8899);
        aSumAndAverage.printSumOddNumbers(1, 100);
        aSumAndAverage.printSumNumbersDivisibleBySeven(1, 100);
        aSumAndAverage.printSumSquares(1, 100);
    }
    
    /**
     * Sum the numbers use a \"for\" loop.
     * @param number
     * @return 
     */
    private void printSumNumbersUsingForLoop(int number)
    {
        long sum = 0L;
        for(int i = 1; i <= number; i++) {
            sum += i;
        }
        System.out.println("Sum the "+number+" numbers use a \"for\" loop.");
        System.out.println("The sum is " + sum);
        System.out.println("The average is "+ ((double) sum / number));
    }
    
    /**
     * Sum the numbers use a "do-while" loop instead of \"for\" loop.
     * @param number
     * @return 
     */
    private void printSumNumbersUsingDoWhileLoop(int number)
    {
        long sum = 0L;
        int  i   = 1;
        do {
            sum += i;
            i++;
        } while (i <= number);        
        System.out.println("Sum the "+number+" numbers use a \"do-while\" loop.");
        System.out.println("The sum is " + sum);
        System.out.println("The average is "+ ((double) sum / number));
    }
    
    /**
     * Sum the numbers use a "while-do" loop instead of \"for\" loop.
     * 
     * @param number
     * @return 
     */
    private void printSumNumbersUsingWhileDoLoop(int number)
    {
        long sum = 0L;
        int  i   = 1;
        while (i <= number) {
            sum += i;
            i++;
        }
        System.out.println("Sum the "+number+" numbers use a \"while-do\" loop.");
        System.out.println("The sum is " + sum);
        System.out.println("The average is "+ ((double) sum / number));
    }
    
    /**
     * Sum the numbers from range.
     * 
     * @param lowerNumber
     * @param upperNumber
     * @return 
     */
    private void printSumNumbersFromRange(int lowerNumber, int upperNumber)
    {
        long count = 0L;
        long sum   = 0L;
        for (int i = lowerNumber; i <= upperNumber; i++) {
            sum += i;
            count++;
        }
        System.out.println("4. Sum numbers from "+lowerNumber+" to "+upperNumber+", and compute the average.");
        System.out.println("The sum is " + sum);
        System.out.printf ("The average is %.2f", ((double) sum / count));
        System.out.println();
    }
    
    
    
    /**
     * Sum only the odd numbers from range, and compute the average.
     * 
     * @param lowerNumber
     * @param upperNumber 
     */
    private void printSumOddNumbers(int lowerNumber, int upperNumber)
    {
        long count = 0L;
        long sum   = 0L;
        for (int i = lowerNumber; i <= upperNumber; i++) {
            if (i % 2 != 0) {
                continue;
            }
            sum += i;
            count++;
        }
        System.out.println("5. Sum only the odd numbers from "+lowerNumber+" to "+upperNumber+", and compute the average.");
        System.out.println("The sum is " + sum);
        System.out.printf ("The average is %.2f", ((double) sum / count));
        System.out.println();
    }
    
    /**
     * Sum numbers from range that is divisible by 7, and compute the average.
     * 
     * @param lowerNumber
     * @param upperNumber 
     */
    private void printSumNumbersDivisibleBySeven(int lowerNumber, int upperNumber)
    {
        long   count = 0L;
        long   sum   = 0L;

        for (int i = lowerNumber; i <= upperNumber; i++) {
            if (i % 7 != 0) {
                continue;
            }
            sum += i;
            count++;
        }
        
        System.out.println("6. Sum numbers from "+lowerNumber+" to "+upperNumber+" that is divisible by 7, and compute the average.");
        System.out.println("The sum is " + sum);
        System.out.printf ("The average is %.2f", ((double) sum / count));
        System.out.println();
    }
    
    /**
     *  Find out the "sum of the squares" of all the numbers from 1 to 100,
     *  i.e. 1*1 + 2*2 + 3*3 + ... + 100*100.
     */
    private void printSumSquares(int lowerNumber, int upperNumber)
    {
        long   count = 0L;
        long   sum   = 0L;

        for (int i = lowerNumber; i <= upperNumber; i++) {
            sum += i*i;
            System.out.println(i*i);
            count++;
        }
        System.out.println("7. Sum of the squares from "+lowerNumber+" to "+upperNumber+".");
        System.out.println("The sum is " + sum);
        System.out.printf ("The average is %.2f", ((double) sum / count));
        System.out.println();
    }
}