30 Pattern Programs In Java That You Should Learn: 2021
Introduction
For aspiring Java professionals, Java Pattern Programs are critical to understand and practice as the pattern-based Java programs help analyze programming ability. In this listicle, we have tried to provide pattern programs in Java with detailed explanations. This blog will be a comprehensive guide for how to print patterns in Java.
Contents at a glance:
- Pyramid Pattern Programs in Java
- Sandglass Java Star Pattern Program
- Right Triangle Star Pattern Programs in Java
- Left Triangle Star Pattern Programs in Java
- Diamond Pattern Program in Java
- Downward Triangle Star Pattern Program in Java
- Mirrored Right Triangle Star Pattern Programs in Java
- Reversed Pyramid Star Pattern Programs in Java
- Right down Mirror Star Pattern Programs in Java
- Diamond Number Pattern Programs in Java
- Alphabet Pattern Programs in Java
- Character Pattern Programs in Java
- Square Pattern Programs in Java
- Pattern Matching Pattern Programs in Java
- String Pattern Programs in Java
- Word Pattern Programs in Java
- Odd Number Pattern Programs in Java
- Pascal’s Triangle Pattern Programs in Java
- Java Number Pattern Programs
- Square Number Pattern Programs in Java
- K Shape Alphabet Pattern Program
- Triangle Character Pattern Program in Java
- Diamond Pattern in Java
- Down triangle star program
- Alphabet A Pattern
- Pattern Programs in Java
- Zeroes & ones Pattern Programs
- Binary Number Rectangle Pattern
- Descending Numbers Pattern Program
- Matrix Pattern programs in java
One of the most essential components of the Java Interview questions has always been Java Pattern Programs. Although they appear to be hard to solve at times, most often than not, they are just really based on mathematical logic and the principles of matrices.Therefore, pattern programs in java are always in high demand.
Patterns can be designed in a variety of creative, architectural, and behavioral ways to provide answers for instantiating an object in the best feasible way for specific conditions, depending on the pattern structure type.
When designing or changing applications or software programs, software designers employ Design Patterns as a prominent problem-solving strategy. It aids in the creation of simple, well-structured software that testers, developers, and users can understand and utilize.
Maintaining and introducing additional attributions in accordance with version requirements is simple; errors may be detected and promptly fixed if they occur. If necessary, developers can reuse programs; work on multiple interfaces and bridge them.
1. Pyramid Pattern Programs in Java
The pyramid is one of the simple pattern programs in Java that is often asked in interviews.
public class JigSawAcademy
{
public static void PyramidPattern(int n)
{
for (int i=0; i<n; i++) // for number of rows(n)
{ for (int j=n-i; j>1; j–) // a loop for spaces
{
System.out.print(” “); //to print space
}
for (int j=0; j<=i; j++ ) //for number of columns
{
System.out.print(“* “); //to print star
}
System.out.println(); //end-line after every row
}
}
public static void main(String args[]) //driver function,
{
int n = 5;
PyramidPattern(n);
}
}
Output:
*
* *
* * *
* * * *
* * * * *
It is one of the easiest pattern printing programs in Java.
2. Sandglass Java Star Pattern Program
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter the number of rows: “);
int rows = sc.nextInt();
for (int i= 0; i<= rows-1 ; i++)
{
for (int j=0; j <i; j++)
{
System.out.print(” “);
}
for (int k=i; k<=rows-1; k++) { System.out.print(“*” + ” “); } System.out.println(“”); } for (int i= rows-1; i>= 0; i–)
{
for (int j=0; j< i ;j++)
{
System.out.print(” “);
}
for (int k=i; k<=rows-1; k++)
{
System.out.print(“*” + ” “);
}
System.out.println(“”);
}
sc.close();
}
}
Output:
* * * * *
* * * *
* * *
* *
*
*
* *
* * *
* * * *
* * * * *
3. Right Triangle Star Pattern Programs in Java
public class RightTrianglePattern
{
public static void main(String args[])
{
// the rows to print
int i, j, row=6;
//the outer loop for rows
for(i=0; i<row; i++)
{
//the inner loop for columns
for(j=0; j<=i; j++)
{
//to prints stars
System.out.print(“* “);
}
// print new line
System.out.println();
}
}
}
Output:
*
* *
* * *
* * * *
* * * * *
4. Left Triangle Star Pattern Programs in Java
public class JigSawAcademy
{
public static void printStars(int n)
{
int i, j;
for(i=0; i<n; i++) //an outer loop for number of rows(n)
{ for(j=2*(n-i); j>=0; j–) // an inner loop for spaces
{
System.out.print(” “); // to print space
}
for(j=0; j<=i; j++) // an inner loop for columns
{
System.out.print(“* “); // to print star
}
System.out.println(); // end-line after every row
}
}
public static void main(String args[])
{
int n = 5;
printStars(n);
}
}
Output:
*
* *
* * *
* * * *
* * * * *
5. Diamond Pattern Program in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String args[])
{
int n, i, j, space = 1;
System.out.print(“Enter the number of rows: “);
Scanner s = new Scanner(System.in);
n = s.nextInt();
space = n – 1;
for (j = 1; j<= n; j++)
{
for (i = 1; i<= space; i++)
{
System.out.print(” “);
}
space–;
for (i = 1; i <= 2 * j – 1; i++)
{
System.out.print(“*”);
}
System.out.println(“”);
}
space = 1;
for (j = 1; j<= n – 1; j++)
{
for (i = 1; i<= space; i++)
{
System.out.print(” “);
}
space++;
for (i = 1; i<= 2 * (n – j) – 1; i++)
{
System.out.print(“*”);
}
System.out.println(“”);
}
}
}
Output:
*
***
*****
*******
*********
*******
*****
***
*
6. Downward Triangle Star Pattern Program in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter the number of rows: “); //to take input from user
int rows = sc.nextInt();
for (int i= rows-1; i>=0 ; i–)
{
for (int j=0; j<=i; j++)
{
System.out.print(“*” + ” “);
}
System.out.println();
}
sc.close();
}
}
Output:
* * * * *
* * * *
* * *
* *
*
7. Mirrored Right Triangle Star Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter number of rows: “); // to take input from user
int rows = sc.nextInt();
for (int i= 0; i<= rows; i++)
{
for (int j=1; j<=rows-i; j++)
{
System.out.print(” “);
}
for (int k=0;k<=i;k++)
{
System.out.print(“*”);
}
System.out.println(“”);
}
sc.close();
}
}
Output:
*
**
***
****
*****
******
8. Reversed Pyramid Star Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter the number of rows: “);
int rows = sc.nextInt();
for (int i= 0; i<= rows-1 ; i++)
{
for (int j=0; j<=i; j++)
{
System.out.print(” “);
}
for (int k=0; k<=rows-1-i; k++)
{
System.out.print(“*” + ” “);
}
System.out.println();
}
sc.close();
}
}
Output:
* * * * *
* * * *
* * *
* *
*
9. Right down Mirror Star Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in); // to take input
System.out.println(“Enter number of rows: “);
int rows = sc.nextInt();
for (int i= rows; i>= 1; i–)
{
for (int j=rows; j>i;j–)
{
System.out.print(” “);
}
for (int k=1;k<=i;k++)
{
System.out.print(“*”);
}
System.out.println(“”);
}
sc.close();
}
}
Output:
*****
****
***
**
*
10. Diamond Number Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args) {
for (int i = 1; i <= 4; i++)
{
int n = 4;
for (int j = 1; j<= n – i; j++) { System.out.print(” “); } for (int k = i; k >= 1; k–)
{
System.out.print(k);
}
for (int l = 2; l <= i; l++) { System.out.print(l); } System.out.println(); } for (int i = 3; i >= 1; i–)
{
int n = 3;
for (int j = 0; j<= n – i; j++) { System.out.print(” “); } for (int k = i; k >= 1; k–)
{
System.out.print(k);
}
for (int l = 2; l <= i; l++)
{
System.out.print(l);
}
System.out.println();
}
}
}
Output:
1
212
32123
4321234
32123
212
1
11. Alphabet Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
{
int alphabet = 65;
for (int i = 0; i <= 5; i++)
{
for (int j = 0; j <= i; j++)
{
System.out.print((char) (alphabet + j) + ” “);
}
System.out.println();
}
}
}
Output:
A
A B
A B C
A B C D
A B C D E
A B C D E F
12. Character Pattern Programs in Java
Character pattern programs in java using for loop prints the patterns in shapes of characters.
import java.util.Scanner;
public class JigSawAcademy
{public static void main(String[] args)
{
for (int i = 5; i >= 0; i–)
{
int alphabet = 65;
for (int j = 0; j <= i; j++)
{
System.out.print((char) (alphabet + j) + ” “);
}
System.out.println();
}
for (int i = 0; i<= 5; i++)
{
int alphabet = 65;
for (int j = 0; j <= i; j++)
{
System.out.print((char) (alphabet + j) + ” “);
}
System.out.println();
}
}
}
Output:
A B C D E F
A B C D E
A B C D
A B C
A B
A
A
A B
A B C
A B C D
A B C D E
A B C D E F
13. Square Pattern Programs in Java
import java.io.*;
class JigSawAcademy{
//print hollow rectangle
static void print_rectangle(int n, int m)
{
int i, j;
for (i = 1; i <= n; i++)
{
for (j = 1; j <= m; j++)
{
if (i == 1 || i == n ||
j == 1 || j == m)
System.out.print(“*”);
else
System.out.print(” “);
}
System.out.println();
}
}
//Driver program
public static void main(String args[])
{
int rows = 6, columns = 20;
print_rectangle(rows, columns);
}
}
Output:
********************
* *
* *
* *
* *
********************
14. Pattern Matching Pattern Programs in Java
public class REmatch {
public static void main(String[] argv) {
String patt = “Q[^u]\\d+\\.”;
Pattern r = Pattern.compile(patt);
String line = “Order QT300. Now!”;
Matcher m = r.matcher(line);
if (m.find()) {
System.out.println(patt + ” matches \”” +
m.group(0) +
“\” in \”” + line + “\””);
} else {
System.out.println(“NO MATCH”);
}
}
}
Output:
Q[\^u]\d+\. matches “QT300.” in “Order QT300. Now!”
15. String Pattern Programs in Java
package com.javainterviewpoint;
import java.util.Scanner;
public class Pattern24
{
public static void main(String[] args)
{
// to create a new Scanner object
Scanner scanner = new Scanner(System.in);
// to get the String from the user
System.out.println(“Enter the String which needs to be printed “);
String input = scanner.nextLine();
System.out.println(“** Printing the pattern… **”);
for (int i = 1; i <= input.length(); i++)
{
for (int j = input.length(); j > i; j–)
{
System.out.print(” “);
}
for (int k = i * 2 – 1; k >= 1; k–)
{
System.out.print(input.charAt(i – 1));
}
System.out.println(“”);
}
}
}
Output:
Enter the string which needs to be printed
JAVA
** Printing the pattern… **
J
AAA
VVVVV
AAAAAAA
16. Word Pattern Programs in Java
public boolean wordPattern(String pattern, String str) {
String[] arr = str.split(” “);
//to prevent out of boundary problem
if(arr.length != pattern.length())
return false;
HashMap<Character, String> map = new HashMap<Character, String>();
for(int i=0; i<pattern.length(); i++){
char c = pattern.charAt(i);
if(map.containsKey(c)){
String value = map.get(c);
if(!value.equals(arr[i])){
return false;
}
}else if (map.containsValue(arr[i])){
return false;
}
map.put(c, arr[i]);
}
return true;
}
17. Odd Number Pattern Programs in Java
import java.util.Scanner;
class Pattern {
static void display(int n)
{
int i, j, k;
for (i = 1; i <= n; i++) {
for (j = 1, k = i; j <= i; j++, k–) {
if (k % 2 == 0) {
// to display the numbers
System.out.print(j);
}
else {
//to display the stars
System.out.print(“*”);
}
}
System.out.print(“\n”);
}
}
// Driver Code
public static void main(String[] args)
{
// to get n
int n = 5;
// to print the pattern
display(n);
}
}
Output:
*
1
*
2
*
1*3*
*
2*4
18. Pascal’s Triangle Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args) {
int n = 5;
for (int i = 0; i < n; i++) {
int number = 1;
System.out.printf(“%” + (n – i) * 2 + “s”, “”);
for (int j = 0; j <= i; j++) {
System.out.printf(“%4d”, number);
number = number * (i – j) / (j + 1);
}
System.out.println();
}
}
}
Output:
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
19. Java Number Pattern Programs
Pattern number programs in java print numbers in patterns like square, Damon, sandglass, and triangle.
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args) {
int i, j, k = 1;
for (i = 1; i <= 5; i++) {
for (j = 1; j< i + 1; j++) {
System.out.print(k++ + ” “);
}
System.out.println();
}
}
}
Output:
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
20. Square Number Pattern Programs in Java
import java.util.Scanner;
public class SquareNumber2 {
private static Scanner sc;
public static void main(String[] args)
{
int side, i = 0, j;
sc = new Scanner(System.in);
System.out.print(” Please Enter any Side of a Square : “);
side = sc.nextInt();
while(i < side)
{
j = 0;
while(j < side)
{
System.out.print(“1”);
j++;
}
i++;
System.out.print(“\n”);
}
}
}
Output:
1 2 3
1 2 3
1 2 3
Similarly, there are and that you can print in the same way.
21. K Shape Alphabet Pattern Program
import java.util.Scanner;
public class JigSawAcademy
{public static void main(String[] args)
{
for (int i = 5; i >= 0; i–)
{
int alphabet = 65;
for (int j = 0; j <= i; j++)
{
System.out.print((char) (alphabet + j) + ” “);
}
System.out.println();
}
for (int i = 0; i<= 5; i++)
{
int alphabet = 65;
for (int j = 0; j <= i; j++)
{
System.out.print((char) (alphabet + j) + ” “);
}
System.out.println();
}
}
}
A B C D E F
A B C D E
A B C D
A B C
A B
A
A
A B
A B C
A B C D
A B C D E
A B C D E F
22. Triangle Character Pattern Program in Java
public class JigSawAcademy
{
public static void main(String[] args)
{
for (int i = 0; i <= 5; i++) { int alphabet = 65; for (int j = 5; j > i; j–)
{
System.out.print(” “);
}
for (int k = 0; k <= i; k++)
{
System.out.print((char) (alphabet + k) + ” “);
}
System.out.println();
}
}
}
Output:
A
A B
A B C
A B C D
A B C D E
A B C D E F
23. Diamond Pattern in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args) {
char[] letter = { ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’,
‘K’, ‘L’, ‘M’, ‘N’, ‘O’, ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’, ‘U’, ‘V’,
‘W’, ‘X’, ‘Y’, ‘Z’ };
int letter_number = 0;
String[] diamond = new String[26]; // create an array of strings
System.out.print(“Enter any Character between A to Z : “);
Scanner reader = new Scanner(System.in);
try {
char user_letter = reader.next(“[A-Z]”).charAt(0);
// to search for letter number in the array letter
for (int i = 0; i < letter.length; i++) {
if (letter[i] == user_letter) {
letter_number = i;
break;
}
}
// to construct a diamond
for (int i = 0; i <= letter_number; i++) {
diamond[i] = “”;
// to add initial spaces
for (int j = 0; j < letter_number – i; j++) {
diamond[i] += ” “;
}
// to add letter
diamond[i] += letter[i];
// to add space between letters
if (letter[i] != ‘A’) {
for (int j = 0; j < 2 * i – 1; j++) { diamond[i] += ” “; } // to add letter diamond[i] += letter[i]; }
// to draw the first section of the diamond
System.out.println(diamond[i]); } for (int i = letter_number – 1; i >= 0; i–)
{
// to draw the second part of the diamond
// to write the diamondArray in reverse order
System.out.println(diamond[i]);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
reader.close();
}
}
}
Output:
A
B B
C C
D D
E E
F F
E E
D D
C C
B B
A
24. Down triangle star program
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter the number of rows: “);
int rows = sc.nextInt();
for (int i=rows; i>= 1 ; i–)
{
for (int j = i; j < rows ; j++) {
System.out.print(” “);
}
for (int k = 1; k <= (2*i -1) ;k++) {
if( k==1 || i == rows || k==(2*i-1)) {
System.out.print(“*”);
}
else {
System.out.print(” “);
}
}
System.out.println(“”);
}
sc.close();
}
}
Output:
*********
* *
* *
* *
*
25. Alphabet A Pattern
import java.util.Scanner;
public class JigSawAcademy
{
// To print alphabet A pattern
void display(int n)
{
// an outer for loop for number of lines
for (int i = 0; i<=n; i++) {
// an inner for loop for logic execution
for (int j = 0; j<= n / 2; j++) {
// to print two column lines
if ((j == 0 || j == n / 2) && i != 0 ||
// to print first line of alphabet
i == 0 && j != n / 2 ||
// to print middle line
i == n / 2)
System.out.print(“*”);
else
System.out.print(” “);
}
System.out.println();
}
}
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
JigSawAcademy a = new JigSawAcademy();
a.display(7);
}
}
Output:
**
* *
***
* *
* *
* *
26. Pattern Programs in Java
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in); // rows value from the user
System.out.println(“Enter the number of rows: “);
int rows = sc.nextInt();
for (int i = 1; i <= rows; i++)
{
for (int j = 1; j <= i; j++)
{
System.out.print(i+” “);
}
System.out.println();
}
sc.close();
}
}
Output:
1
2 2
3 3 3
4 4 4 4
5 5 5 5 5
27. Zeroes & ones Pattern Programs
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter the number of rows: “);
int rows = sc.nextInt();
for (int i = 1; i <= rows; i++)
{
for (int j = 1; j <= i; j++)
{
if(j%2 == 0)
{
System.out.print(0);
}
else
{
System.out.print(1);
}
}
System.out.println();
}
sc.close();
}
}
Output:
1
10
101
1010
10101
28. Binary Number Rectangle Pattern
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println(“Enter the number of rows: “);
int rows = sc.nextInt();
for (int i = 1; i <= rows; i++)
{
int num;
if(i%2 == 0)
{
num = 0;
for (int j = 1; j <= rows; j++)
{
System.out.print(num);
num = (num == 0)? 1 : 0;
}
}
else
{
num = 1;
for (int j = 1; j <= rows; j++)
{
System.out.print(num);
num = (num == 0)? 1 : 0;
}
}
System.out.println();
}
sc.close();
}
}
Output:
10101
01010
10101
01010
10101
29. Descending Numbers Pattern Program
import java.util.Scanner;
public class JigSawAcademy
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
//take a row-value from the user
System.out.println(“How many rows do you want in this pattern?”);
int rows = sc.nextInt();
System.out.println(“Here is your pattern….!!!”);
for (int i = 1; i <= rows; i++)
{
for (int j = rows; j >= i; j–)
{
System.out.print(j+” “);
}
System.out.println();
}
//to close all the resources
sc.close();
}
}
Output:
7 6 5 4 3 2 1
7 6 5 4 3 2
7 6 5 4 3
7 6 5 4
7 6 5
7 6
7
30. Matrix Pattern programs in java
import java.io.*;
class JigSawAcademy
{
//to print the pattern
static void printPattern(int n)
{
// the number of rows & columns to print
int s = 2 * n – 1;
// upper half of matrix
for (int i = 0;
i < (s / 2) + 1; i++)
{
int m = n;
// the decreasing part
for (int j = 0; j < i; j++)
{
System.out.print(m + ” “);
m–;
}
// the constant part
for (int k = 0;
k < s – 2 * i; k++)
{
System.out.print(n – i + ” “);
}
// the increasing part.
m = n – i + 1;
for (int l = 0; l < i; l++)
{
System.out.print(m + ” “);
m++;
}
System.out.println();
}
// lower half of the matrix
for (int i = s / 2 – 1;
i >= 0; i–)
{
// the decreasing part
int m = n;
for (int j = 0; j < i; j++)
{
System.out.print(m + ” “);
m–;
}
// the constant part.
for (int k = 0;
k < s – 2 * i; k++)
{
System.out.print(n – i + ” “);
}
// the decreasing part
m = n – i + 1;
for (int l = 0; l < i; l++)
{
System.out.print(m + ” “);
m++;
}
System.out.println();
}
}
// the driver code
public static void main (String[] args)
{
int n = 3;
printPattern(n);
}
}
Output:
3 3 3 3 3
3 2 2 2 3
3 2 1 2 3
3 2 2 2 3
3 3 3 3 3
Conclusion
This blog is a collection of different pattern programs in java; From basic pattern programs in java to difficult pattern programs in java. If you wish to learn more about Java programming, check out our Master Certificate in Full Stack Development program! The course offers Guaranteed Placement, live online instructor-led classes, and more!
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