Program to print half Diamond star pattern

Given an integer N, the task is to print half-diamond-star pattern.

*
**
***
****
*****
******
*****
****
***
**
*

Examples:

```Input: N = 3
Output:
*
**
***
**
*

Input: N = 6
Output:
*
**
***
****
*****
******
*****
****
***
**
*
```

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The idea is to break the pattern into two halves that is upper half and lower half. Then print then separately with the help of the loops. The key observation for printing the upper half and lower half is described as below:

• Upper half: The upper half of the pattern contains star ‘*’ in increasing order where ith line contains following number of star:
```Number of '*' in ith line =
```
• Lower Half: The lower half of the pattern contains star ‘*’ in decreasing order where ith line contains following number of star:
```Number of '*' in ith line =
```
• Below is the implementation of the above approach:

C++

 `// C++ implementation to print the ` `// half diamond star pattern ` ` `  `#include ` ` `  `using` `namespace` `std; ` ` `  `// Function to print the ` `// half diamond star pattern ` `void` `halfDiamondStar(``int` `N) ` `{ ` `    ``int` `i, j; ` ` `  `    ``// Loop to print the upper half ` `    ``// diamond pattern ` `    ``for` `(i = 0; i < N; i++) { ` `        ``for` `(j = 0; j < i + 1; j++) ` `            ``cout << ``"*"``; ` `        ``cout << ``"\n"``; ` `    ``} ` ` `  `    ``// Loop to print the lower half ` `    ``// diamond pattern ` `    ``for` `(i = 1; i < N; i++) { ` `        ``for` `(j = i; j < N; j++) ` `            ``cout << ``"*"``; ` `        ``cout << ``"\n"``; ` `    ``} ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``int` `N = 5; ` ` `  `    ``// Function Call ` `    ``halfDiamondStar(N); ` `} `

Java

 `// Java implementation to print the ` `// half diamond star pattern ` `import` `java.util.*; ` ` `  `class` `GFG{ ` ` `  `// Function to print the ` `// half diamond star pattern ` `static` `void` `halfDiamondStar(``int` `N) ` `{ ` `    ``int` `i, j; ` ` `  `    ``// Loop to print the upper half ` `    ``// diamond pattern ` `    ``for` `(i = ``0``; i < N; i++) ` `    ``{ ` `        ``for` `(j = ``0``; j < i + ``1``; j++) ` `             ``System.out.print(``"*"``); ` `        ``System.out.print(``"\n"``); ` `    ``} ` ` `  `    ``// Loop to print the lower half ` `    ``// diamond pattern ` `    ``for` `(i = ``1``; i < N; i++)  ` `    ``{ ` `        ``for` `(j = i; j < N; j++) ` `             ``System.out.print(``"*"``); ` `        ``System.out.print(``"\n"``); ` `    ``} ` `} ` ` `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int` `N = ``5``; ` ` `  `    ``// Function Call ` `    ``halfDiamondStar(N); ` `} ` `} ` ` `  `// This code is contributed by Rohit_ranjan `

Python3

 `# Python3 implementation to print the  ` `# half diamond star pattern  ` ` `  `# Function to print the  ` `# half diamond star pattern  ` `def` `halfDiamondStar(N): ` `     `  `    ``# Loop to print the upper half  ` `    ``# diamond pattern  ` `    ``for` `i ``in` `range``(N): ` ` `  `        ``for` `j ``in` `range``(``0``, i ``+` `1``): ` `            ``print``(``"*"``, end ``=` `"") ` `        ``print``() ` ` `  `    ``# Loop to print the lower half  ` `    ``# diamond pattern  ` `    ``for` `i ``in` `range``(``1``, N): ` ` `  `        ``for` `j ``in` `range``(i, N): ` `            ``print``(``"*"``, end ``=` `"") ` `        ``print``() ` ` `  `# Driver Code  ` `N ``=` `5``;  ` ` `  `# Function Call  ` `halfDiamondStar(N); ` ` `  `# This code is contributed by skylags `

C#

 `// C# implementation to print the ` `// half diamond star pattern ` `using` `System; ` ` `  `class` `GFG{ ` ` `  `// Function to print the ` `// half diamond star pattern ` `static` `void` `halfDiamondStar(``int` `N) ` `{ ` `    ``int` `i, j; ` ` `  `    ``// Loop to print the upper half ` `    ``// diamond pattern ` `    ``for``(i = 0; i < N; i++) ` `    ``{ ` `       ``for``(j = 0; j < i + 1; j++) ` `           ``Console.Write(``"*"``); ` `       ``Console.Write(``"\n"``); ` `    ``} ` ` `  `    ``// Loop to print the lower half ` `    ``// diamond pattern ` `    ``for``(i = 1; i < N; i++)  ` `    ``{ ` `       ``for``(j = i; j < N; j++) ` `           ``Console.Write(``"*"``); ` `       ``Console.Write(``"\n"``); ` `    ``} ` `} ` ` `  `// Driver Code ` `public` `static` `void` `Main(String[] args) ` `{ ` `    ``int` `N = 5; ` ` `  `    ``// Function Call ` `    ``halfDiamondStar(N); ` `} ` `} ` ` `  `// This code is contributed by Rohit_ranjan `

Output:

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

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Improved By : Rohit_ranjan, skylags