Why is it important for a grammar to be unambiguous?

In the computer science, the ambiguous grammar is the which exist in the string in the parse tree structure and it is also known as context free grammar. But the ambiguous grammar is the undesirable because the tree derivation basically provide the useful data about the program semantics.

The ambiguity is one of the property of the grammar that usually fine the equivalent unambiguous grammar and also provide the conflicting data in the derivation tree.