Results 1 to 5 of 5
  1. #1
    Magic101 is offline Member
    Join Date
    May 2008
    Posts
    3
    Rep Power
    0

    Question Pascal Triangle help

    hey everyone i am new to Java that's why i need any help i can get.
    i need to fill up the function Rows returns ragged array containing the first n rows of Pascal's triangle.
    i tried playing around with it but considering i am totally new to this i have no idea if i am doing it right or how it should be implemented. I think i am doing way too much of what needs to be done.

    can someone please take a look and based on what's given in the main function right now tell me what Rows should look like...

    Java Code:
    public class Pascal {
        public static int[][] Rows(int n){
        	int[][] pt = new int[n][];
        	for (int i = 0; i < n; i++) {
                pt[i] = new int[i + 1];                            // Construct row i.
                pt[i][0] = 1;                              // Leftmost value of row i.
                for (int j = 1; j < i; j++) {
                  pt[i][j] = pt[i - 1][j - 1] + pt[i - 1][j];  // Sum 2 entries above.
                }
                pt[i][i] = 1;                             // Rightmost value of row i.
              }
              return pt;
        }
    
     
        public static void main(String[] args) {
            if (args.length != 1) {
              System.out.println("usage: java " + Pascal.class.getName() + " rows");
              System.exit(1);
            }
            int n = Integer.parseInt(args[0]);
            if (n > 0) {
              int[][] pascal = Rows(n);
              for (int[] row : pascal) {
        	for (int v : row) System.out.print(v + " ");
        	System.out.println("");
              }
            }
          }
    }

    when i try running this of course nothing gets printed except the usage:java message.

    thanks a lot :)

  2. #2
    Zosden's Avatar
    Zosden is offline Senior Member
    Join Date
    Apr 2008
    Posts
    384
    Rep Power
    7

    Default

    I would use recursion to generate the Fibonacci numbers then just print them out.
    My IP address is 127.0.0.1

  3. #3
    Magic101 is offline Member
    Join Date
    May 2008
    Posts
    3
    Rep Power
    0

    Default

    Quote Originally Posted by Zosden View Post
    I would use recursion to generate the Fibonacci numbers then just print them out.
    thanks for response... but would you mind actually showing me how it should be done.. i am clueless oh that part :confused:
    Main function stays as it is other functions is the one that needs modification...

    thanks.

  4. #4
    Zosden's Avatar
    Zosden is offline Senior Member
    Join Date
    Apr 2008
    Posts
    384
    Rep Power
    7

    Default

    Heres a nice template for recursion

    Java Code:
    public <modifier> recusiveAlg(You need some sort of parameter)
    {
         if(some sort of stopping criteria)
         {
             return something;
         }
         else
         {
             return recursiveAlg(your parameter - 1)
         }
    }
    Try to do this with Fibonacci numbers

    hint: Fibonacci's numbers are the previous fib number + the one before the pervious fib number.
    My IP address is 127.0.0.1

  5. #5
    Magic101 is offline Member
    Join Date
    May 2008
    Posts
    3
    Rep Power
    0

    Smile

    Quote Originally Posted by Zosden View Post
    Heres a nice template for recursion

    Java Code:
    public <modifier> recusiveAlg(You need some sort of parameter)
    {
         if(some sort of stopping criteria)
         {
             return something;
         }
         else
         {
             return recursiveAlg(your parameter - 1)
         }
    }
    Try to do this with Fibonacci numbers

    hint: Fibonacci's numbers are the previous fib number + the one before the pervious fib number.
    hmmm correct me if i'm wrong but isn't it already implemented in the main function?

    Java Code:
    if (n > 0) {
              int[][] pascal = Rows(n);
              for (int[] row : pascal) {
        	for (int v : row) System.out.print(v + " ");
        	System.out.println("");
    all Rows has to do is to generate the array somehow to decide the row number...
    Last edited by Magic101; 05-01-2008 at 07:58 PM.

Similar Threads

  1. change the square to triangle java
    By anotsu in forum New To Java
    Replies: 3
    Last Post: 07-09-2009, 11:17 AM
  2. Triangle
    By jkswebsite in forum New To Java
    Replies: 8
    Last Post: 01-10-2009, 02:08 PM
  3. Replies: 0
    Last Post: 04-12-2008, 08:39 PM
  4. Making triangle
    By banie in forum New To Java
    Replies: 4
    Last Post: 02-02-2008, 11:23 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •