/**  
 * This program prints out a 3N+1 sequence starting from a positive 
 * integer specified by the user.  It also counts the number of 
 * terms in the sequence, and prints out that number.
 */
public class ThreeN1 {

    public static void main(String[] args) {                

        int N;       // for computing terms in the sequence
        int counter; // for counting the terms

        System.out.print("Starting point for sequence: ");
        N = TextIO.getlnInt();
        while (N <= 0) {
            System.out.print("The starting point must be positive. Please try again: ");
            N = TextIO.getlnInt();
        }
        // At this point, we know that N &gt; 0

        counter = 0;
        while (N != 1) {
            if (N % 2 == 0)
                N = N / 2;
            else
                N = 3 * N + 1;
            System.out.println(N);
            counter = counter + 1;
        }

        System.out.println();
        System.out.print("There were ");
        System.out.print(counter);
        System.out.println(" terms in the sequence.");

    }  // end of main()

}  // end of class ThreeN1