Differences between Synthesized and Inherited Attributes

In Syntax Directed Definition, two attributes are used one is Synthesized attribute and another is inherited attribute. An attribute is said to be Synthesized attribute if its parse tree node value is determined by the attribute value at child nodes whereas An attribute is said to be Inherited attribute if its parse tree node value is determined by the attribute value at parent and/or siblings node. Now, we shall see the comparison between Synthesized Attributes and Inherited Attributes. The comparison between these two attributes are given below:

S.NO	Synthesized Attributes	Inherited Attributes
1.	An attribute is said to be Synthesized attribute if its parse tree node value is determined by the attribute value at child nodes.	An attribute is said to be Inherited attribute if its parse tree node value is determined by the attribute value at parent and/or siblings node.
2.	The production must have non-terminal as its head.	The production must have non-terminal as a symbol in its body.
3.	A synthesized attribute at node n is defined only in terms of attribute values at the children of n itself.	A Inherited attribute at node n is defined only in terms of attribute values of n’s parent, n itself, and n’s siblings.
4.	It can be evaluated during a single bottom-up traversal of parse tree.	It can be evaluated during a single top-down and sideways traversal of parse tree.
5.	Synthesized attributes can be contained by both the terminals or non-terminals.	Inherited attributes can’t be contained by both, It is only contained by non-terminals.
6.	Synthesized attribute is used by both S-attributed SDT and L-attributed SDT.	Inherited attribute is used by only L-attributed SDT.
7.