Program to print window pattern

Print the pattern in which there is a hollow square and plus sign inside it. The pattern will be as per the n i.e. number of rows given as shown in the example. 

Examples:

Input : 6
Output : * * * * * *
         *   * *   * 
         * * * * * * 
         * * * * * * 
         *   * *   * 
         * * * * * *

Input : 7
Output : * * * * * * * 
         *     *     * 
         *     *     * 
         * * * * * * * 
         *     *     * 
         *     *     * 
         * * * * * * *

Approach:

• We will start a for loop up till n and inside this also there is for loop up till n.
• In this simply we have to check if the row is first or last or column is first or last, then print “*”.
• Now we have to check for the middle row and column.
• So when n is odd, we will have a middle row and column and if row or column is in middle then we will print “*”.
• If n is even, then rows or columns if equal to these values n/2 and (n/2)+1, then we will print “*”.
• Else everywhere we have to print ” “(space).

Below is the implementation. 

C++14

// C++ program to print the pattern
// hollow square with plus inside it
// window pattern
#include <bits/stdc++.h>
using namespace std;

// Function to print pattern n means
// number of rows which we want
void window_pattern (int n)
{
    int c, d;

    // If n is odd then we will have
    // only one middle element
    if (n % 2 != 0)
    {
        c = (n / 2) + 1;
        d = 0;
    }

    // If n is even then we will have two
    // values
    else
    {
        c = (n / 2) + 1;
        d = n / 2 ;
    }

    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= n; j++)
        {

            // If i,j equals to corner row or
            // column then "*"
            if (i == 1 || j == 1 ||
                i == n || j == n)
                cout << "* ";

            else
            {

                // If i,j equals to the middle
                // row or column then  "*"
                if (i == c || j == c)
                    cout << "* ";

                else if (i == d || j == d)
                    cout << "* ";

                else
                    cout << "  ";
            }
        }
        cout << '\n';
    }
}

// Driver Code
int main()
{
    int n = 7;

    window_pattern(n);
    return 0;
}

// This code is contributed by himanshu77

Java

// Java program to print the pattern
// hollow square with plus inside it
// window pattern
class GFG
{

  // Function to print pattern n means
  // number of rows which we want
  static void window_pattern (int n)
  {
    int c, d;

    // If n is odd then we will have
    // only one middle element
    if (n % 2 != 0)
    {
      c = (n / 2) + 1;
      d = 0;
    }

    // If n is even then we will have
    // two values
    else
    {
      c = (n / 2) + 1;
      d = n / 2 ;
    }
    for(int i = 1; i <= n; i++)
    {
      for(int j = 1; j <= n; j++)
      {

        // If i,j equals to corner row
        // or column then "*"
        if (i == 1 || j == 1 ||
            i == n || j == n)
          System.out.print("* ");
        else
        {

          // If i,j equals to the middle
          // row or column then  "*"
          if (i == c || j == c)
            System.out.print("* ");
          else if (i == d || j == d)
            System.out.print("* ");
          else
            System.out.print("  ");
        }
      }
      System.out.println();
    }
  }

  // Driver code
  public static void main(String[] args)
  {
    int n = 7;
    window_pattern(n);
  }
}

// This code is contributed by divyeshrabadiya07

Python3

# Python3 program to print the pattern
# hollow square with plus inside it
# window pattern


# function to print pattern n means
# number of rows which we want
def window_pattern(n):

    # if n is odd then we will have
    # only one middle element
    if n % 2 != 0:
        c = ( n // 2 ) + 1
        d = 0

    # if n is even then we will have two
    # values
    else:
        c = ( n // 2 ) + 1
        d = ( n // 2 )

    for i in range( 1 , n + 1 ):
        for j in range( 1 , n + 1 ):

            # if i,j equals to corner row or
            # column then "*"
            if i == 1 or j == 1 or i == n or j == n:
                print("*",end=" ")

            else:

                # if i,j equals to the middle row
                # or column then  "*"
                if i == c or j == c:
                    print("*",end=" ")

                elif i == d or j == d:
                    print("*",end=" ")

                else:
                    print(" ",end=" ")

        print()


# Driver Code
if __name__ == "__main__":
    n = 7
    window_pattern(n)

C#

// C# program to print the pattern
// hollow square with plus inside it
// window pattern
using System;

class GFG{

// Function to print pattern n means
// number of rows which we want
static void window_pattern (int n)
{
    int c, d;

    // If n is odd then we will have
    // only one middle element
    if (n % 2 != 0)
    {
        c = (n / 2) + 1;
        d = 0;
    }

    // If n is even then we will have
    // two values
    else
    {
        c = (n / 2) + 1;
        d = n / 2 ;
    }

    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= n; j++)
        {

            // If i,j equals to corner row
            // or column then "*"
            if (i == 1 || j == 1 ||
                i == n || j == n)
                Console.Write("* ");

            else
            {

                // If i,j equals to the middle
                // row or column then  "*"
                if (i == c || j == c)
                    Console.Write("* ");

                else if (i == d || j == d)
                    Console.Write("* ");

                else
                    Console.Write("  ");
            }
        }
        Console.WriteLine();
    }
}

// Driver code
static void Main()
{
    int n = 7;

    window_pattern(n);
}
}

// This code is contributed by divyesh072019

Javascript

<script>

      // JavaScript program to
      // print the pattern
      // hollow square with
      // plus inside it
      // window pattern

      // Function to print pattern n means
      // number of rows which we want
      function window_pattern(n)
      {
        var c, d;

        // If n is odd then we will have
        // only one middle element
        if (n % 2 != 0) {
          c = parseInt(n / 2 + 1);
          d = 0;
        }

        // If n is even then we will have two
        // values
        else {
          c = parseInt(n / 2 + 1);
          d = parseInt(n / 2);
        }

        for (var i = 1; i <= n; i++) {
          for (var j = 1; j <= n; j++) {
            // If i,j equals to corner row or
            // column then "*"
            if (i == 1 || j == 1 || i == n || j == n)
            document.write("* ");
            else {
              // If i,j equals to the middle
              // row or column then "*"
              if (i == c || j == c)
              document.write("* ");
              else if (i == d || j == d)
              document.write("* ");
              else
              document.write("   ");
            }
          }
          document.write("<br>");
        }
      }

      // Driver Code
      var n = 7;

      window_pattern(n);

</script>

Output :

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

Time complexity: O(n²) 

Auxiliary space: O(1) because it is using constant space for variables