Tree
// Item, Key, Node, Link, Tree types as before // operations on keys #define cmp(k1,k2) ((k1) - (k2)) #define lt(k1,k2) (cmp(k1,k2) < 0) #define eq(k1,k2) (cmp(k1,k2) == 0) #define gt(k1,k2) (cmp(k1,k2) > 0) // standard tree operations Tree newTree(); Tree TreeInsert(Tree, Item); Tree TreeDelete(Tree, Key); int TreeFind(Tree, Key);