Difference Between Structure and Union in C

Difference between structures and unions

This tutorial differentiates between the structures and unions in C programming language.

Difference Between Structure and Union

Structure	Union
A structure is a collection of data members possibly of different data types grouped together under a single name.	A union is a special type of variable in C which contains data members possibly of different data types, also grouped under a single name.
A structure variable acts like a record.	A union variable acts like a radio button which is used to access or store only one out of multiple options.
All members of structure occupy distinct memory locations.	All members of union share the same memory location.
All members of the structure can be initialized at a time.	Only the first member of union can be initialized.
All the members of a structure can be accessed and can be assigned some values at a time.	Only one member of union can be accessed and can be assigned a value at a time.
The size of the structure variable is the sum of the sizes of individual data members of the structure.	The size of a union variable is the size of the largest data member.