Create mirror image of a tree.

Solution #1: A mirror image of a tree is a tree in which left and right children of each node get swapped. This problem has a recursive nature and therefore can be easily solved with recursion. The algorithm will look like this,

- check if  the node is NULL, if yes then return, continue otherwise
- swap left and right child
- repeat for left and right child

Here is the code,

void mirror(node *root)
{
    if(root == NULL)
        return;

    //swap left and right children
    node* temp = root->left;
    root->left = root->right;
    root->right = temp;

    //recursively call on left and right child
    mirror(root->left);
    mirror(root->right);
}