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Pattern printing is a great way to improve logic-building skills in Java. It's widely used in coding interviews, competitive programming, and as a fundamental exercise to understand loops and conditional structures.

In this blog, we'll explore some of the most common and interesting pattern problems, with explanations and Java code implementations.

Square Pattern:

A square pattern is one of the simplest patterns, where the same character or number is printed in a grid format. The key idea behind this pattern is using two nested loops:

  • The outer loop controls the rows.
  • The inner loop controls the columns and prints the character in each row.

This is useful for understanding the basics of nested loops.

import java.util.Scanner;
public class SquarePattern {
void pattern(int n) {
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
System.out.print("* ");
}
System.out.println();
}
}
public static void main(String[] args) {
int n;
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of rows and columns : ");
n = sc.nextInt();
SquarePattern p = new SquarePattern();
p.pattern(n);
}
}
view raw SquarePattern.java hosted with ❤ by GitHub

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Right-Angled Triangle Pattern:

This pattern builds a right-angled triangle using increasing rows of symbols.

  • The number of symbols in each row is equal to the row index.
  • The outer loop runs for the total number of rows, while the inner loop prints the increasing count of symbols.

It helps in understanding incremental loop structures.

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import java.util.Scanner;
public class RightAngledTriangle {
void pattern(int n) {
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= i; j++) {
System.out.print("* ");
}
System.out.println();
}
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of rows in a triangle: ");
int n = sc.nextInt();
RightAngledTriangle p = new RightAngledTriangle();
p.pattern(n);
}
}
view raw RightAngledTriangle.java hosted with ❤ by GitHub

Inverted Pyramid Pattern:

n this pattern, we start with the maximum number of symbols in the first row, decreasing in each subsequent row.

  • The outer loop runs from the maximum row count down to 1.
  • The inner loop ensures that each row has fewer symbols than the previous one.

It helps in practicing decremental looping techniques.

import java.util.Scanner;
class InvertedPyramid {
void pattern(int n) {
for (int i = 0; i < n; i++) {
for (int j = n; j > i; j--) {
System.out.print("* ");
}
System.out.println();
}
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of rows : ");
int n = sc.nextInt();
InvertedPyramid pyramid = new InvertedPyramid();
pyramid.pattern(n);
}
}
view raw InvertedPyramid.java hosted with ❤ by GitHub

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Right-Angled Number Pyramid 1:

This pattern is a variation of the right-angled triangle but uses numbers instead of symbols.

  • The numbers increase with each row, providing an easy way to understand number-based pattern printing.

It's helpful for working with number sequences in nested loops.

import java.util.Scanner;
class RightAngledNumberPyramid {
void pattern(int n) {
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= i; j++) {
System.out.print(j + " ");
}
System.out.println();
}
}
public static void main(String[] args) {
int n;
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of rows in a pyramid: ");
n = sc.nextInt();
RightAngledNumberPyramid r = new RightAngledNumberPyramid();
r.pattern(n);
}
}
view raw RightAngledNumberPyramid.java hosted with ❤ by GitHub

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Right-Angled Number Pyramid 2:

This is another numeric pyramid but prints numbers in increasing order, forming a right-angled shape.

  • The outer loop controls the number of rows.
  • The inner loop ensures that numbers in each row increase progressively.

This enhances logical understanding of number-based patterns.

import java.util.Scanner;
class RightAngledNumberPyramid2 {
public void pattern(int n) {
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= i; j++) {
System.out.print(i + " ");
}
System.out.println();
}
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of rows: ");
int n=sc.nextInt();
RightAngledNumberPyramid2 p = new RightAngledNumberPyramid2();
p.pattern(n);
}
}
view raw RightAngledNumberPyramid2.java hosted with ❤ by GitHub

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Inverted Number Pyramid:

This pattern is the inverted form of the numeric pyramid.

  • The outer loop runs in decreasing order.
  • The inner loop prints numbers based on the row index.

It is an excellent way to practice decrementing loops and number manipulation.

import java.util.Scanner;
class InvertedNumberPyramid {
void pattern(int n) {
for (int i = 0; i < n; i++) {
for (int j = n; j > i; j--) {
System.out.print(n-j+1+" ");
}
System.out.println();
}
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter the number of rows : ");
int n = sc.nextInt();
InvertedPyramid pyramid = new InvertedPyramid();
pyramid.pattern(n);
}
}
view raw InvertedNumberPyramid.java hosted with ❤ by GitHub

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