Java Tutorials and Java Concept
The pattern similar to Floyd triangle, there is another triangle is called the Pascal triangle named after famous French mathematician Blaise Pascal. But it has a little bit different. Here each row is the summation of the left value and a right value of the previous row. if the above row value is missing then it is taken as 0.
The formula is co = co * (i — j + 1) / j Where i is the row number and j is the element position in that row.
Java program for Pascal triangle
import java.util.*;
public class PascalTriangle
{
public static void main(String args[])
{
int rows, co, i, j;
co = 1;
Scanner sc = new Scanner (System.in);
System.out.println(“Enter the number of rows”);
rows = sc.nextInt();
for(i = 0; i < rows; i++)
{
// print the space
for(j = 1; j < rows — i; j++)
{
System.out.print(“ “);
}
// print value
for(j = 0; j <= i; j++)
{
if (j == 0 || i == 0)
{
co = 1;
}
else
{
co = co * (i — j + 1) / j;
}
// row print
System.out.print(co + “ “);
}
System.out.println();
}
} // end of the main() method
} // end of the class
Output
Enter the number of rows
6
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1
Java program for Pascal triangle with recursive method
In this program, the Pascal triangle is generated with the recursive method pascalTriangle(int i, int j).
In this program, the Pascal triangle is generated with recursive method pascalTriangle(int i, int j).
import java.util.*;
public class PascalTriangleRecursiveMethod
{
//instance variable;
int i, j, k;
public void printRow(int n)
{
for (i = 0; i < n; i++)
{
for (k = 0; k < n — i; k++)
{
// print the space
System.out.print(“ “);
}
for (j = 0; j <= i; j++)
{
System.out.print(pascalTriangle(i, j) + “ “);
}
System.out.println();
}
}
public int pascalTriangle(int i, int j)
{
if (j == 0 || j == i)
{
return 1;
}
else
return pascalTriangle(i — 1, j — 1) + pascalTriangle(i — 1, j);
}
public static void main(String[] args)
{
int rows;
PascalTriangleRecursiveMethod ob = new PascalTriangleRecursiveMethod();
Scanner sc = new Scanner(System.in);
System.out.print(“Enter the number of rows : “);
rows = sc.nextInt();
System.out.println(“Pascal Triangle printed as:”);
System.out.println(“======================”);
ob.printRow(rows);
}
}
Output
Enter the number of rows: 5
Pascal Triangle printed as:
======================
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
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Originally published at https://javaknowhow.blogspot.com.