What is the definition for the height of a tree?

Question

I can\'t seem to find a definitive answer for this, I\'m trying to do some elementary proofs on heaps but here\'s what\'s throwing me off a little bit:

Is an empt

Answer 1

actully a perfect defn for height of tree is d level of leaf of d longest path from root plus 1..accordin 2 this defn f a tree s empty,it wont b havin any level n v cant consider it had zero,coz level of a root s zero ..so empty tree level is -1,than accordin 2 defn its -1+1=0..so ZERO s d height of empty tree...bt n many book they hav given -1 bt no explanation s given