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Java Program to Print Reverse Pyramid Star Pattern
• Last Updated : 17 Mar, 2021

Approach:

1. Get the number of input rows from the user using Scanner Class or BufferedReader Class object.

2. Now run two loops

• Outer loop to iterate through a number of rows as initialized or input is taken from reader class object in java. Now,
• Run an inner loop from 1 to ‘i-1’
• Ru another inner loop from 1 to rows * 2 – (i × 2 – 1)

Illustration:

```Input: number = 7

Output:

*************
***********
*********
*******
*****
***
*```

Methods: We can print a reverse pyramid star pattern using the following methods:

1. Using while loop
2. Using for loop
3. Using do-while loop

Example 1: Using While Loop

## Java

 `// Java program to Print Reverse Pyramid Star Pattern``// Using While loop`` ` `// Importing input output classes``import` `java.io.*;`` ` `// Main class``class` `GFG {`` ` `    ``// Main driver method``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Declaring and initializing variable to``        ``// Size of the pyramid``        ``int` `number = ``7``;`` ` `        ``int` `i = number, j;`` ` `        ``// Nested while loops``        ``// Outer loop`` ` `        ``// Till condition holds true``        ``while` `(i > ``0``) {``            ``j = ``0``;`` ` `            ``// Inner loop``            ``// Condition check``            ``while` `(j++ < number - i) {``                ``// Print whitespaces``                ``System.out.print(``" "``);``            ``}`` ` `            ``j = ``0``;`` ` `            ``// Inner loop``            ``// Condition check``            ``while` `(j++ < (i * ``2``) - ``1``) {``                ``// Print star``                ``System.out.print(``"*"``);``            ``}`` ` `            ``// By now, we reach end of execution for one row``            ``// so next line``            ``System.out.println();`` ` `            ``// Decrementing counter because we want to print``            ``// reverse of pyramid``            ``i--;``        ``}``    ``}``}`
Output
```*************
***********
*********
*******
*****
***
*```

Example 2: Using for Loop

## Java

 `// Java program to print reverse pyramid star pattern``// Using for loop``import` `java.io.*;`` ` `class` `GFG{``     ` `public` `static` `void` `main (String[] args) ``{``     ` `    ``// Size of the pyramid``    ``int` `number = ``7``;``    ``int` `i, j;``     ` `    ``// Outer loop handle the number of rows``    ``for``(i = number; i >= ``1``; i--)``    ``{``         ` `        ``// Inner loop print space``        ``for``(j = i; j < number; j++)``        ``{``            ``System.out.print(``" "``);``        ``}``         ` `        ``// Inner loop print star``        ``for``(j = ``1``; j <= (``2` `* i - ``1``); j++)``        ``{``            ``System.out.print(``"*"``);``        ``}``         ` `        ``// Ending line after each row``        ``System.out.println(``""``);``    ``} ``}``}`
Output
```*************
***********
*********
*******
*****
***
*```

Example 3: Using do-while Loop

## Java

 `// Java program to Print Reverse Pyramid Star Pattern``// Using do-while loop`` ` `// Importing input output classes``import` `java.io.*;`` ` `// Main Class``public` `class` `GFG {`` ` `    ``// Main driver method``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Declare and initialize variable to``        ``// Size of the pyramid``        ``int` `number = ``7``;`` ` `        ``int` `i = number, j;`` ` `        ``// Outer loop iterate until i > 0 is false``        ``do` `{``            ``j = ``0``;`` ` `            ``// First inner do-while loop``            ``do` `{`` ` `                ``// Prints space until j++ < number - i is``                ``// false``                ``System.out.print(``" "``);``            ``} ``while` `(j++ < number - i);``            ``j = ``0``;`` ` `            ``// Second inner do-while loop`` ` `            ``// Inner loop prints star``            ``// until j++ < i * 2 - 2 is false``            ``do` `{`` ` `                ``// print star``                ``System.out.print(``"*"``);``            ``}`` ` `            ``while` `(j++ < i * ``2` `- ``2``);`` ` `            ``// Print whitespace``            ``System.out.println(``""``);``        ``}`` ` `        ``// while of outer 'do-while' loop``        ``while` `(--i > ``0``);``    ``}``}`
Output
``` *************
***********
*********
*******
*****
***
*```

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