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Help with a pattern using nested loops (java)

  1. Mar 23, 2015 #1
    Hey so I have to make a pattern in the shape of a diamond as follow:
    Code (Text):

      1
     123
    12345
     123
      1
     
    So first, I wrote the code without using a variable n as the number of rows ( from an input from the user) but just the constant i = 5 ( I am sorry for the variable names, I made many patterns and this was just trying to get it to work so I didn't mind it as I was going to change everything later)
    Code (Text):


    public class PatternChose {

        public static void main(String[] args) {
            // TODO Auto-generated method stub
            int k = 0, h=2, c=0;
              for (int i=1 ; i<=5 ; i++)
               {
                { for (int u=2 ; u >= i ; u--)
                      System.out.print(" ");
                       h--;
                 for (int j=1  ; j<= i + k ; j++)
                    System.out.print(j);
                 for (int w=2 ; w>= i; w--)
                    System.out.print(" ");
                   
                    }
                    k++;
                    System.out.println();
                    if (h<0)
                        break;}
                  for (int i =2 ; i>=1 ; i--){
                     { for (int l=3 ; l>+i ; l--)
                         System.out.print(" ");
                        for (int m= 0 ; m <=i - c ; m++)
                          System.out.print( m + 1);
                     }
                     c++;
                     System.out.println();
                     
                  }
        }

    }
     
    Then, as this gave the output that I first did up there, I tried to do it with a value inputted by a user:

    Code (Text):

    import java.util.Scanner;


    public class PatternChose {

        public static void main(String[] args) {
            // TODO Auto-generated method stub
            int k = 0, h=2, c=0, row=1;
            Scanner userInput = new Scanner(System.in);
            System.out.println("Please input your value");
              int newUserInput = userInput.nextInt();
              for (int i=1 ; i<=newUserInput ; i++)
               {
                { for (int u=newUserInput - row ; u >= i ; u--)
                      System.out.print(" ");
                       h--;
                 for (int j=1  ; j<= i + k ; j++)
                    System.out.print(j);
                 for (int w=2 ; w>= i; w--)
                    System.out.print(" ");
                   
                    }
                    k++;
                    System.out.println();
                    if (h<0)
                        break;}
                  for (int i =2 ; i>=1 ; i--){
                     { for (int l=3 ; l>+i ; l--)
                         System.out.print(" ");
                        for (int m= 0 ; m <=i - c ; m++)
                          System.out.print( m + 1);
                     }
                     c++;
                     row++;
                     System.out.println();
                     
                  }
        }

    }


     

    But, I'm having an issue while trying to use a value from an input. This is because in my first code, I used the space to the left of the numbers to tell when the program to break to then form a lower triangle. However, I do notice a pattern with the space vs. the number of rows but it doesn't seem like I'd be able to code it as the values always change. ( I don't think I'm making very much sense??)

    Any pointers of what I should do?
     
  2. jcsd
  3. Mar 23, 2015 #2
    Code (Text):


    import java.util.Scanner;


    public class PatternChosen {

        public static void main(String[] args) {
            // TODO Auto-generated method stub
            int rowsForUpperTriangle = 0,  c=1;
            Scanner userInput = new Scanner(System.in);
            System.out.println("Please input your value");
              int newUserInput = userInput.nextInt();
              int h = newUserInput / 2;
              for (int i=1 ; i<=newUserInput ; i++)
               {
                { for (int u=newUserInput / 2 ; u >= i ; u--)
                      System.out.print(" ");
                       h--;
                 for (int j=1  ; j<= i + rowsForUpperTriangle ; j++)
                    System.out.print(j);
                 for (int SpaceToRight=2 ; SpaceToRight>= i; SpaceToRight--)
                    System.out.print(" ");
                   
                    }
                rowsForUpperTriangle++;
                    System.out.println();
                    if (h<0)
                        break;}
                  for (int i =newUserInput / 2 ; i>=1 ; i--){
                     { for (int l=newUserInput / 2 ; l>=i ; l--)
                         System.out.print(" ");
                        for (int m= 1  ; m <= newUserInput - (2 * c) ; m++)
                          System.out.print( m );
                     }
                     c++;
                     System.out.println();
                     
                  }
        }

    }

     
    Anyone can tell me how I could reduce this code? I know there are shorter way to code a diamond but this is what I got, which is pretty messy for something so simple I think..
     
  4. Mar 24, 2015 #3

    gabbagabbahey

    User Avatar
    Homework Helper
    Gold Member

    Hmmm... that seems like a lot of extra loops and processing. Before changing your code, maybe write down in words what you are trying to accomplish.

    It looks like for an input of 5, your desired output is 5 lines each with 5 characters (either spaces or integers)....how many (outer) loops would you expect to need to write 5 lines one at a time? How many (inner) loops would you expect to need to write 5 characters one at a time?
    How do things change for an even input (number of rows) like 4?
     
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