C Programming - Structures, Unions, Enums - Discussion

All are user-defined datatypes which allow the user to create their own datatype which can be a combination of int, float, char, etc.

Please, explain about union?

Which is better to use structure or union? Any one explain in detail.

Array.
Pointer.
Structure.
Union.
Enum.

Are the user defined or secondary types of data type in C?

These are the user defined data types. But enumeration only allocate in integer data types. Then how does is allocated for new data types for others?

In short structures are used to share different memory locations for variable and union is used to allocate large memory for all variables.

Structures: Structure is denied as a collection of similar elements with different data types. The syntax of structure is :

struct book
{
int pages;
char name;
char author;
int edition;
}b;
Unions: It is a special data type which looks like a structure but are different from each other .
The syntax of union is :
union book
{
char name;
int pages;
int edition;
};
union book b;

The major difference between is there sizes.

In structures all the sizes of attributes are considered where as in case of unions only data type with max size is considered.

Enum: These are the special variables which can assume values which have been previously defined.

Syntax is:

enum month{jan=1, feb, march, april, may}.

enum month this_month;

This_month=feb;

Because these are user defined data type that use to define another data type.

Please tell the proper difference between structure and enum and then union and enum?

Hi, what is an array?