Pascal's Triangle Format

Question

The assignment is to create Pascal's Triangle without using arrays. I have the method that produces the values for the triangle below. The method accepts an integer for the maximum number of rows the user wants printed.

public static void triangle(int maxRows) {
    int r, num;
    for (int i = 0; i <= maxRows; i++) {
        num = 1;
        r = i + 1;
        for (int col = 0; col <= i; col++) {
            if (col > 0) {
                num = num * (r - col) / col;    
            }
            System.out.print(num + " ");
        }
        System.out.println();
    }
}

I need to format the values of the triangle such that it looks like a triangle:

              1
            1   1
          1   2   1
        1   3   3   1
      1   4   6   4   1
    1   5  10  10   5   1
  1   6  15  20  15   6   1

I can't for the life of me figure out how to do that. Please answer keeping in mind that I'm a beginner in Java programming.

Answer 1

In each row you will need to print:

• n spaces
• m numbers
• n spaces

Your job is to figure out n (which will be zero in the last line) and m based on row number.

[This is more like a comment but I needed more formatting options than comments provide]

Answer 2

You can try this code in java. It's simple :)

public class PascalTriangle {

public static void main(String[] args) {
    int rows = 10;

    for(int i =0;i<rows;i++) {
        int number = 1;
        System.out.format("%"+(rows-i)*2+"s","");
        for(int j=0;j<=i;j++) {
             System.out.format("%4d",number);
             number = number * (i - j) / (j + 1);

        }
        System.out.println();
    }
  }
}

Answer 3

public static void main(String[] args)
{
    int a, num;

    for (int i = 0; i <= 4; i++) 
    {
        num = 1;
        a = i + 1;

        for(int j=4;j>0;j--)
        { 
            if(j>i)
                System.out.print(" ");
        }

        for (int j = 0; j <= i; j++) 
        {
            if (j > 0) 
                num = num * (a - j) / j;   

            System.out.print(num + " ");
        }
        System.out.println();
    } 
}

Code perfectly prints pascal triangle

Answer 4

This is a good start, where it's homework, I'll leave the rest to you:

int maxRows = 6;
int r, num;
for (int i = 0; i <= maxRows; i++) {
    num = 1;
    r = i + 1;
    //pre-spacing
    for (int j = maxRows - i; j > 0; j--) {
        System.out.print(" ");
    }
    for (int col = 0; col <= i; col++) {
        if (col > 0) {
            num = num * (r - col) / col;
        }
        System.out.print(num + " ");
    }
    System.out.println();
}

Answer 5

import java.util.*;
class Mine
{
    public static void main(String ar[])
    {
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        for(int i=1;i<n;i++)
        {
            int size=1;
            for(int j=1;j<=i;j++)
            {
                int a[]=new int[size];
                int d[]=new int[size];
                for(int k=1;k<=size;k++)
                {
                    a[1]=1;
                    a[size]=1;

                    for(int p=1;p<=size;p++)
                    {
                        d[p]=a[p];
                    }

                    if(size>=3)
                    {
                        for(int m=2;m<size;m++)
                        {
                            a[m]=d[m]+d[m-1];
                        }
                    }
                }

                for(int y=0;y<size;y++)
                {
                    System.out.print(a[y]);
                }
                System.out.println(" ");
            }
            ++size;
        }
    }
}

Answer 6

public class HelloWorld{

     public static void main(String []args){
       int s=7;
       int k=1;
       int r;

       for(int i=1;i<=s;i++){
           int num=1;
           r=i;
           int col=0;
           for(int j=1;j<=2*s-1;j++){

               if(j <= s-i)
               System.out.print("  ");
               else if(j >= s+i)
               System.out.print("  ");
               else{
                   if(k%2 ==0){
                       System.out.print("  ");

                   }
                   else{
                        if (col > 0) {
                            num = num * (r - col) / col;    
                        }

                    System.out.print(num+" ");
                       col++;
                   }
               k++;
               }
           }
           System.out.println("");
           k=1;
       }




     }
}