This article is aimed at giving a Java implementation for pattern printing.
Simple pyramid pattern
Java
import java.io.*;// Java code to demonstrate star patternspublic class GeeksForGeeks{ // Function to demonstrate printing pattern public static void printStars(int n) { int i, j; // outer loop to handle number of rows // n in this case for(i=0; i<n; i++) { // inner loop to handle number of columns // values changing acc. to outer loop for(j=0; j<=i; j++) { // printing stars System.out.print("* "); } // ending line after each row System.out.println(); } } // Driver Function public static void main(String args[]) { int n = 5; printStars(n); }} |
Output
* * * * * * * * * * * * * * *
Time Complexity: O(n^2)
Space Complexity: O(1)
Method: Using while loop
Java
// java program to print simple pyramid pattern using while// loopimport java.io.*;class GFG { public static void main(String[] args) { int r = 1, c = 0, n = 5; // the while loop check the conditions until the // condition is false. if it is true then enter in // to loop and execute the statements while (r <= n) { while (c <= r - 1) { // printing the required pattern System.out.print("* "); c++; } r++; c = 0; // new line after each row System.out.println(); } }}// this code is contributed by gangarajula laxmi |
Output
* * * * * * * * * * * * * * *
Time Complexity: O(N^2),The outer while loop iterates N times, while the inner while loop iterates N-1 times. Hence, the total time complexity of the program will be O(N2).
Space Complexity: O(1),No extra space is required.
Method#2: Using Recursion
Java
// Java code to demonstrate star pattern// using Recursionimport java.io.*;class GFG { // function to print a row static void printRow(int num) { // base case if (num == 0) return; System.out.print("* "); // recursively calling printRow() printRow(num - 1); } // function to print the pattern static void pattern(int n, int i) { // base case if (n == 0) return; printRow(i); System.out.println(); // recursively calling pattern() pattern(n - 1, i + 1); } // Driver code public static void main(String[] args) { int n = 5; pattern(n, 1); }}// this code is contributed by Shivesh Kumar Dwivedi |
Output
* * * * * * * * * * * * * * *
Time Complexity: O(N^2)
Auxiliary Space: O(N^2)
After 180 degree rotation
Java
import java.io.*;// Java code to demonstrate star patternpublic class GeeksForGeeks{ // Function to demonstrate printing pattern public static void printStars(int n) { int i, j; // outer loop to handle number of rows // n in this case for(i=0; i<n; i++) { // inner loop to handle number spaces // values changing acc. to requirement for(j=2*(n-i); j>=0; j--) { // printing spaces System.out.print(" "); } // inner loop to handle number of columns // values changing acc. to outer loop for(j=0; j<=i; j++) { // printing stars System.out.print("* "); } // ending line after each row System.out.println(); } } // Driver Function public static void main(String args[]) { int n = 5; printStars(n); }} |
Output
*
* *
* * *
* * * *
* * * * *
The time complexity of the program is O(n^2) because there are two nested loops, each running n times.
The space complexity is O(1).
Method#3: Using Recursion
Java
// Java code to demonstrate star pattern//using Recursionimport java.util.*; public class GeeksForGeeks{ // function to print spaces static void printSpace(int space) { // base case if (space == 0) { return; } System.out.print(" " + " "); // recursively calling printSpace() printSpace(space - 1); } // function to print stars static void printStars(int star) { // base case if (star == 0) { return; } System.out.print("* "); // recursively calling printStars() printStars(star - 1); } // function to print the pattern static void pattern(int n, int num) { // base case if (n == 0) { return; } printSpace(n - 1); printStars(num - n + 1); System.out.println(); // recursively calling pattern() pattern(n - 1, num); } // Driver code public static void main(String args[]) { int n = 5; pattern(n, n); }}//this code is contributed by Shivesh Kumar Dwivedi |
Output
*
* *
* * *
* * * *
* * * * *
Printing Triangle
Java
import java.io.*;// Java code to demonstrate star patternpublic class GeeksForGeeks{ // Function to demonstrate printing pattern public static void printTriangle(int n) { // outer loop to handle number of rows // n in this case for (int i=0; i<n; i++) { // inner loop to handle number spaces // values changing acc. to requirement for (int j=n-i; j>1; j--) { // printing spaces System.out.print(" "); } // inner loop to handle number of columns // values changing acc. to outer loop for (int j=0; j<=i; j++ ) { // printing stars System.out.print("* "); } // ending line after each row System.out.println(); } } // Driver Function public static void main(String args[]) { int n = 5; printTriangle(n); }} |
Output
* * * * * * * * * * * * * * *
Method#4: Using Recursion
Java
// Java code to demonstrate star pattern// using recursionimport java.util.*;public class GeeksForGeeks { // function to print spaces static void printSpace(int space) { // base case if (space == 0) return; System.out.print(" "); // recursively calling printSpace() printSpace(space - 1); } // function to print asterisks static void printStar(int asterisk) { // base case if (asterisk == 0) return; System.out.print("* "); // recursively calling printStar() printStar(asterisk - 1); } // function to print the pattern static void pattern(int n, int num) { // base case if (n == 0) return; printSpace(n - 1); printStar(num - n + 1); System.out.println(""); // recursively calling pattern() pattern(n - 1, num); } // Driver code public static void main(String[] args) { int n = 5; pattern(n, n); }}// this code is contributed by Shivesh Kumar Dwivedi |
Output
* * * * * * * * * * * * * * *
Print Reverse Of Pyramid
Java
//MainFunctionpublic class ReversePyramid{ public static void main(String[] args) { int rows = 6; // Number of Rows we want to print //Printing the pattern for (int i = 1; i <= rows; i++) { for (int j = 1; j < i; j++) { System.out.print(" "); } for (int j = i; j <= rows; j++) { System.out.print(j+" "); } System.out.println(); } } } |
Output
1 2 3 4 5 6
2 3 4 5 6
3 4 5 6
4 5 6
5 6
6
Pattern of Number with Mirror Image
Java
//MainFunctionpublic class ReversePattern{ public static void main(String[] args) { int rows = 7; // Number of Rows we want to print //Printing the pattern for (int i = 1; i <= rows; i++) { for (int j = 1; j < i; j++) { System.out.print(" "); } for (int j = i; j <= rows; j++) { System.out.print(j+" "); } System.out.println(); } //Printing the reverse pattern for (int i = rows-1; i >= 1; i--) { for (int j = 1; j < i; j++) { System.out.print(" "); } for (int j = i; j <= rows; j++) { System.out.print(j+" "); } System.out.println(); } }} |
Output
1 2 3 4 5 6 7
2 3 4 5 6 7
3 4 5 6 7
4 5 6 7
5 6 7
6 7
7
6 7
5 6 7
4 5 6 7
3 4 5 6 7
2 3 4 5 6 7
1 2 3 4 5 6 7
Number Pattern
Java
import java.io.*;// Java code to demonstrate number patternpublic class GeeksForGeeks{ // Function to demonstrate printing pattern public static void printNums(int n) { int i, j,num; // outer loop to handle number of rows // n in this case for(i=0; i<n; i++) { // initialising starting number num=1; // inner loop to handle number of columns // values changing acc. to outer loop for(j=0; j<=i; j++) { // printing num with a space System.out.print(num+ " "); //incrementing value of num num++; } // ending line after each row System.out.println(); } } // Driver Function public static void main(String args[]) { int n = 5; printNums(n); }} |
Output
1 1 2 1 2 3 1 2 3 4 1 2 3 4 5
Method5: Using while loop
Java
// java program to print number pattern using while// loopimport java.io.*;class GFG { public static void main(String[] args) { int r = 1, c = 1, n = 5; // the while loop check the conditions until the // condition is false. if it is true then enter in // to loop and execute the statements while (r <= n) { while (c <= r ) { // printing the required pattern System.out.print(c+" "); c++; } r++; c = 1; // new line after each row System.out.println(); } }} |
Output
1 1 2 1 2 3 1 2 3 4 1 2 3 4 5
Numbers without re assigning
Java
import java.io.*;// Java code to demonstrate star patternpublic class GeeksForGeeks{ // Function to demonstrate printing pattern public static void printNums(int n) { // initialising starting number int i, j, num=1; // outer loop to handle number of rows // n in this case for(i=0; i<n; i++) { // without re assigning num // num = 1; for(j=0; j<=i; j++) { // printing num with a space System.out.print(num+ " "); // incrementing num at each column num = num + 1; } // ending line after each row System.out.println(); } } // Driver Function public static void main(String args[]) { int n = 5; printNums(n); }} |
Output
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Printing Christmas Tree Using Pyramid
Java
class PrintChristmasTree{ //Value 5 is permanently provided to height variable public static final int height = 5; //Main Function public static void main(String[] args) { //Assigning Width int width = 5; //Assigning Space int space = width*5; int x = 1; //Code to Print Upper Part of the Tree i.e. Pyramids. for(int a = 1;a <= height ;a++){ for(int i = x;i <= width;i++){ for(int j = space;j >= i;j--){ System.out.print(" "); } for(int k = 1;k <= i;k++){ System.out.print("* "); } System.out.println(); } x = x+2; width = width+2; } //Printing Branch of Christmas Tree for(int i = 1;i <= 4;i++){ for(int j = space-3;j >= 1;j--){ System.out.print(" "); } for(int k= 1;k <= 4;k++){ System.out.print("* "); } System.out.println(); } }} |
Output
*
* *
* * *
* * * *
* * * * *
* * *
* * * *
* * * * *
* * * * * *
* * * * * * *
* * * * *
* * * * * *
* * * * * * *
* * * * * * * *
* * * * * * * * *
* * * * * * *
* * * * * * * *
* * * * * * * * *
* * * * * * * * * *
* * * * * * * * * * *
* * * * * * * * *
* * * * * * * * * *
* * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * * *
* * * *
* * * *
* * * *
* * * *
Time complexity: O(h*w*w) for given height h and width w
Auxiliary Space: O(1)
This article is contributed by Nikhil Meherwal(S. Shafaq). If you like neveropen and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the neveropen main page and help other Geeks.
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