What are the differences between structures and union?

What are the differences between structures and union?
Ans: A structure variable contains each of the named members, and its size is large enough to hold all the members. Structure elements are of same size.
A union contains one of the named members at a given time and is large enough to hold the largest member. Union element can be of different sizes.

Difference Between Stucture and Union :

Structure	Union
i. Access Members
We can access all the members of structure at anytime.	Only one member of union can be accessed at anytime.
ii. Memory Allocation
Memory is allocated for all variables.	Allocates memory for variable which variable require more memory.
iii. Initialization
All members of structure can be initialized	Only the first member of a union can be initialized.
iv. Keyword
'struct' keyword is used to declare structure.	'union' keyword is used to declare union.
v. Syntax
struct struct_name { structure element 1; structure element 2; ---------- ---------- structure element n; }struct_var_nm;	union union_name { union element 1; union element 2; ---------- ---------- union element n; }union_var_nm;
vi. Example
struct item_mst { int rno; char nm[50]; }it;	union item_mst { int rno; char nm[50]; }it;

Blog Author: Vijay Kumar

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