Program to swap upper diagonal elements with lower diagonal elements of matrix.

Given a square matrix, swap upper diagonal elements of matrix with lower diagonal elements of matrix.

Examples : 

Input: 2 3 5 6
 4 5 7 9
 8 6 4 9
 1 3 5 6

Output: 2 4 8 1
 3 5 6 3
 5 7 4 5
 6 9 9 6

Input: 1 2 3 
 4 5 6
 7 8 9

Output: 1 4 7
 2 5 8
 3 6 9

Below is the implementation of above idea : 

2 4 8 1 
3 5 6 3 
5 7 4 5 
6 9 9 6 

Time Complexity: O(N²)
Auxiliary Space: O(1)