A data structure, is a group of related data. A graph is a group of two sets, the set of nodes and set of edges. As an abstract data type, you may define oper

A data structure, is a group of related data. A graph is a group of two sets, the set of nodes and set of edges. As an abstract data type, you may define operations on the data structure (aka abstract data type). In case of graph, for example, you can define connectivity check (existence of an edge). And graph theory provides plenty more. And set (in set theoretic sense) is also a data structure, you may define the membership check as on operation on that. On the other hand, a data type is a tag that a compiler associates with raw bits and bytes on the memory in order to operate on them. Examples, datetime is a data type, string is a data type, array is a data type, numbers are data type, these are not data structures. These are language primitives. Further graph is superseded by hi-graph (which is foundation for relational data bases and tuple algebra), and subseded by for example DAGs and trees. To build an edge in a graph, you need something that could point to something. Like A points to B, the most fundamental way to capture this mapping is by using pointers (that is the address of B, stored at a known location accessible by A). A->B or A.B are just syntactic elements that underlie this. Arrays, Matrices, Structs, Strings, are all made possible by pointers. Pointers are a data type, it tags the value (usually in range 0..usize), as being an address of something else in the memory. Pointers are not data structures. I should say primitives vs non-primitives if that makes the difference between what is data type vs data structure.