/********************************************************************
 * Matt Kretchmar
 * March 24, 2006
 * RecursionExamples.java
 * This program illustrates how to compute superSum(n) using two 
 * different methods: iterative and recursive.
 ********************************************************************/
import java.util.Scanner;

class RecursionExamples
{
    /****************************************************************
     * main
     ****************************************************************/
    public static void main ( String args[] )
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter n:");
        int n = keyboard.nextInt();
        System.out.println("SSI("+n+") = " + superSumIterative(n) );
        System.out.println("SSR("+n+") = " + superSumRecursive(n) );
    }
    
    /****************************************************************
     * superSumIterative
     * This method uses iteration (loops) to compute superSum(n).
     * s(n) = 1 + 2 + ... + n
     ****************************************************************/
    public static int superSumIterative ( int n )
    {
        int sum = 0;
        for ( int i = 1; i <= n; i++ )
            sum = sum + i;
        return sum;
    }
    
    /****************************************************************
     * superSumRecursive
     * This method uses recursion to compute superSum(n)
     * Base case:       if n = 1, then superSum(1) = 1
     * Recursive case:  otherwise      superSum(n) = n + superSum(n-1)
     ****************************************************************/
    public static int superSumRecursive ( int n )
    {
        if ( n == 1 ) return 1;
        else return ( n + superSumRecursive(n-1) );
    }
}