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

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

Examples:

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

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

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 i^th 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 i^th 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 <iostream>    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:

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

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