Print Pencil Shape Pattern in Java

The pencil pattern is another pattern created from asterisk symbols using loop and other logical concepts. It is usually asked to draw pattern through a program.

We use the following approach to write the code for it:

Take input from the user and store it into a variable, say row.
We use a nested loop to print the pencil where the first loop is responsible for the number of rows and the second loop is responsible for the number of columns.

We print the pencil pattern in two ways, i.e., by using the static star character and by using the user input character.

Let's understand both of them one by one to understand how we can use static and user input characters:

Static Star Character

PencilPatternExample1.java

// import required classes and package if any
import java.util.Scanner;

// create class PencilPatternExample1 to print pencil pattern by using static star character 
public class PencilPatternExample1{
    
	// main() method start
	public static void main(String[] args){
		
		// declare variables 
		int rows;
		
		// create Scanner class object to take input from the user
		Scanner scan = new Scanner(System.in);
		System.out.print("Enter number of rows: ");
		
		// take input from user and store it into rows variable
		rows = scan.nextInt();
		
		//call drawPencilPattern() method of the PencilPattern class by creating an instance of the class
		PencilPattern obj = new PencilPattern();
		obj.drawPencilPattern(rows);
    
    	}
}

// create a separate class for Pencil pattern
class PencilPattern{
		
	// create user-defined method for drawing pattern
	public void drawPencilPattern(int rows){
		
		// declare variables
		int h;
		
		// use for loop from -row to +row
		for(int i = -rows; i <= rows; i++) 
		{
			h = i;
			
			// for loop for columns
			for(int j = 0; j <= rows; j++)
			{
				// check whether the value of h is less than j
				if(h <= j)
					System.out.print("* ");
				else
					System.out.print(" ");
			}
			 System.out.println("");
		}
	}		
}

Output:

User Input Character

PencilPatternExample2.java

import java.util.Scanner;
// create class PencilPatternExample2 to print pencil pattern by using user input character 
public class PencilPatternExample2{    
	// main() method start
	public static void main(String[] args){
		// declare variables 
		int rows;
		// create Scanner class object to take input from the user
		Scanner scan = new Scanner(System.in);
		// take input from user and store it into rows variable
		System.out.print("Enter number of rows: ");
		rows = scan.nextInt();		
		System.out.print("Enter any character : ");
		char ch = scan.next().charAt(0);
		//call drawPencilPattern() method of the PencilPattern class by creating an instance of the class
		PencilPattern obj = new PencilPattern();
		obj.drawPencilPattern(rows, ch);
    }
}
// create a separate class for Pencil pattern
class PencilPattern{		
	// create user-defined method for drawing pattern
	public void drawPencilPattern(int rows, char ch){		
		// declare variables
		int h;
		// use for loop from -row to +row
		for(int i = -rows; i <= rows; i++) 
		{
			h = i;
			// for loop for columns
			for(int j = 0; j <= rows; j++)
			{
				// check whether the value of h is less than j
				if(h <= j)
					System.out.print(ch+" ");
				else
					System.out.print(" ");
			}
			 System.out.println("");
		}
	}		
}

Output:

Explanation:

Let's understand how each iteration of the for loop works in the above code to print the pencil pattern.

Enter number of rows: 2

Enter any character: @

Iteration-I

The 1^st iteration will be start from i = -2 and execute till i <= 2.
The value of i, i.e., -2, will be stored in a variable, say h.
Th second for loop will iterate from j = 0 till j <= row.
Condition h <= j determines the star to print on the screen. So, In the first iteration of the main for loop, this condition will be satisfied three times and print three-star on the screen.

Iteration-II

The 1^st iteration will be start from i = -1 and execute till i <= 2.
The value of i, i.e., -1, will be stored in a variable, say h.
Th second for loop will iterate from j = 0 till j <= row.
Condition h <= j will be satisfied three times and print three-star on the screen.

Iteration-III

The 1^st iteration will be start from i = 0 and execute till i <= 2.
The value of i, i.e., 0, will be stored in a variable, say h.
Th second for loop will iterate from j = 0 till j <= row.
Condition h <= j will be satisfied three times and print three-star on the screen else print space.

Iteration-IV

The 1^st iteration will be start from i = 1 and execute till i <= 2.
The value of i, i.e., 1, will be stored in a variable, say h.
Th second for loop will iterate from j = 0 till j <= row.
Condition h <= j will be satisfied two times and print two stars on the screen else print space.

Iteration-V

The 1^st iteration will be start from i = 2 and execute till i <= 2.
The value of i, i.e., 2, will be stored in a variable, say h.
Th second for loop will iterate from j = 0 till j <= row.
Condition h <= j will be satisfied only one time and print one star on the screen else print space.

After the 5^th iteration, i will be 3, and the first for loop condition will be false. At last, the pencil pattern will print on the console.

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