Mirror image of a binary tree

Question

Suppose there is a tree:

             1
            / \\
           2   3
              / \\
             4   5

Then the mirror image will

Answer 1

Here is my function. Do suggest if any better solution:

void mirrorimage(struct node *p)
{
    struct node *q;
    if(p!=NULL)
    {
        q=swaptrs(&p);
        p=q;
        mirrorimage(p->left);
        mirrorimage(p->right);
    }
}

struct node* swaptrs(struct node **p)
{
    struct node *temp;
    temp=(*p)->left;
    (*p)->left=(*p)->right;
    (*p)->right=temp;
    return (*p);
}