C++ Program To Print The Diamond Shape

Given a number n, write a program to print a diamond shape with 2n-1 rows.
Examples : 

Input: 5
Output:

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

Time Complexity: O(n*n) since we are traversing rows and columns of a grid for printing spaces ' ' and star '*'.
Auxiliary Space: O(1), No extra space used.