Count Number of Non Leaf Nodes of a given Tree ?

Question

How can we count Number of Non Leaf Nodes of a given Tree ?

Example
            40
            /\
           /  \
         20    60
         / \    \
       10  30   80
                 \
                 90

Answer => 4

Answer 1

We can directly find Internal nodes by using this function(Assuming it as binary tree)

int NonLeafCount(node* node)
{
    if((node == NULL) || (node->left == NULL && node->right==NULL)) return 0;
    else return 1+NonLeafCount(node->left) + NonLeafCount(node->right);
}

Answer 2

unsigned int getLeafCount(struct node* node)
{
  if(node == NULL)       
    return 0;
  if(node->left == NULL && node->right==NULL)      
    return 1;            
  else
    return getLeafCount(node->left)+
           getLeafCount(node->right);      
}

Now subtract it from total number of nodes so same function will serve two purpose count leaf nodes or count non leaf node.