Java Program to Print a Pyramid

1. Introduction

In this post, we will explore how to write a Java program that prints a pyramid pattern using asterisks (*). This type of program is a useful for beginners, offering a practical way to learn nested loops and control structures in Java. By creating a pyramid, we will understand how to manipulate output on the console to create shapes and patterns, a fundamental skill in programming that can be applied in various contexts.

2. Program Steps

1. Initialize the necessary variables for the number of rows in the pyramid.

2. Use a for loop to iterate over the rows of the pyramid.

3. Inside the loop, use two additional for loops: one to print spaces and another to print asterisks (*), thereby forming the pyramid shape.

4. Compile and run the program to see the pyramid pattern printed on the console.

3. Code Program

public class PyramidPattern {
    public static void main(String[] args) {
        int rows = 5; // Number of pyramid rows

        for(int i = 0; i < rows; i++) { // Loop for each row
            for(int j = rows - i; j > 1; j--) { // Loop for spaces
                System.out.print(" "); // Printing space
            }
            for(int k = 0; k <= i; k++) { // Loop for asterisks
                System.out.print("* "); // Printing asterisk and space
            }
            System.out.println(); // New line after each row
        }
    }
}

Output:

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

Explanation:

1. The program initializes with a fixed number of rows (rows = 5).

2. It uses a for loop to iterate through each row. The iteration starts from 0 to maintain the proper count for spaces and asterisks.

3. For each row, a nested for loop first prints the required number of spaces to align the asterisks in a pyramid shape. The number of spaces decreases as the row number increases (for(int j = rows - i; j > 1; j--)).

4. Another nested for loop prints the asterisks (*) and a space to form the pyramid pattern. The number of asterisks increases with each row (for(int k = 0; k <= i; k++)).

5. After printing the required spaces and asterisks for a row, a newline character (System.out.println()) is used to move to the next line.

6. This process repeats until the pyramid pattern is completed for the specified number of rows.