How to Print Pyramid Star Pattern in Java

Learn how to print Pyramid Star Pattern in Java using nested loops. This Java program creates a full pyramid of stars (*) based on the number of rows entered by the user.

Code Explanation (Step-by-Step)

  • Create a Scanner class object to accept user input.
  • Read the number of rows using the sc.nextInt() method.
  • Use an outer for loop to iterate through each row.
  • Use the first inner loop to print the required leading spaces.
  • Use the second inner loop to print stars in each row.
  • The first row contains 1 star, and each subsequent row contains 2 more stars than the previous row (2 * i – 1).
  • Print a new line after each row to form the pyramid shape.
				
					import java.util.Scanner;

public class PyramidStar {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        System.out.println("Enter the number of rows:");
        int row = sc.nextInt();

        for (int i = 1; i <= row; i++) {

            // Print leading spaces
            for (int j = (row - i); j >= 1; j--) {
                System.out.print(" ");
            }

            // Print stars
            for (int k = 1; k <= (2 * i - 1); k++) {
                System.out.print("* ");
            }

            System.out.println();
        }

        sc.close();
    }
}
				
			
				
					Output:- 
Enter the number of rows:- 6

     * 
    * * * 
   * * * * * 
  * * * * * * * 
 * * * * * * * * * 
* * * * * * * * * * *

Java 8 Program to Print Pyramid Star Pattern

				
					import java.util.Scanner;
import java.util.stream.IntStream;

public class PyramidStarPattern {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        System.out.print("Enter the number of rows: ");
        int rows = sc.nextInt();

        IntStream.rangeClosed(1, rows).forEach(i -> {

            IntStream.range(0, rows - i)
                     .forEach(j -> System.out.print(" "));

            IntStream.rangeClosed(1, (2 * i - 1))
                     .forEach(k -> System.out.print("* "));

            System.out.println();
        });

        sc.close();
    }
}

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FAQ
What is a Pyramid Star Pattern in Java?
A Pyramid Star Pattern is a pattern program that prints stars in a pyramid shape using nested loops. Each row contains more stars than the previous row.
Which loop is used to print a Pyramid Star Pattern?
Nested for loops are commonly used. One loop controls rows, while inner loops print spaces and stars.
Why do we use (2 * i – 1) in the program?
This formula generates odd numbers (1, 3, 5, 7, …), which helps create the pyramid shape.
Can we print a Pyramid Pattern using a while loop?
Yes, a Pyramid Star Pattern can also be implemented using while loops instead of for loops.
What is the time complexity of a Pyramid Star Pattern program?
The time complexity is O(n²) because nested loops are used.

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