UNIONS

UNIONS:

Unions are same as structures in some aspects i.e., union is also a collection of different datatypes of elements stored under a single name but the major difference between union and structure is in terms of their storage.

            In structure, each member has its own storage location where as in a union all the members use the same location.

            All the members of the structure can be initialized at the same time but a union can handle only one member at a time. Since, the members of the union share the same memory.

            Declaration of a union is same as that of structure declaration except that the keyword used is union.

Syntax:-

union tagname

{

datatype member 1;

datatype member 2;

:

datatype member n;

};

Eg.,

 union student

{

int rollno;

float avg;

}s1;

The storage is allocated for the member  which occupies largest memory. Here, the union contains two datatypes int and float. Since, the largest is float and it occupies 4 bytes, s1 is allocated 4 bytes.