Question

I need for my output to be the first 100 pentagonal numbers, ten per row , counting in succession. As it stands my output just repeats itself, i am sure this is a simple answer but i cant seem to come up with it. This was homework and already graded but i would like to figure it out for me to learn. Thanks in advance for any input and help.

package chapter_5;

/**
 *
 * @author jason
 */
public class Five_One {


    public static void main(String[] args) {
        for (int k = 1; k < 11; k++) {
            for (int n = 1; n < 11; n++) {
                System.out.print(getPentagonalNumber(n)+ "\t");
            }
            System.out.println();

        }        
 }

    public static int getPentagonalNumber(int n) {
        return  n * (3 * n - 1) / 2;

  }

} 

Answer 1

you are repeatedly calling getPentagonalNumber() with numbers in range [1,10], instead of calling numbers in increasing range. can be solved by adding 10*k [and running k from 0 to 10 instead 1 to 11]

public static void main(String[] args) {
        for (int k =0; k < 10; k++) { //range is [0,10) instead [1,11)
            for (int n = 1; n < 11; n++) {
                System.out.print(getPentagonalNumber((10*k)+n)+ "\t"); //10*k + n instead of n
            }
            System.out.println();

        }        
}