**Solution:**

tree_height(mynode *p) {

if(p==NULL)return(0);

if(p->left){h1=tree_height(p->left);}

if(p=>right){h2=tree_height(p->right);}

return(max(h1,h2)+1); }

The degree of the leaf is zero. The degree of a tree is the max of its element degrees. A binary tree of height n, h > 0, has at least h and at most (2^h -1) elements in it. The height of a binary tree that contains n, n>0, elements is at most n and atleast log(n+1) to the base 2.

Log(n+1) to the base 2 = h

n = (2^h - 1)