Difference between Structure and Union in C

Confused between structure and union, Don’t worry we are here to fend your confusion.

What is structure?

Structure is a user-defined data type, which is a collection of variables of different types under a single name.

Defining structure

To Define a structure in c we have to use the Struct keyword.

Syntax

struct structure_name 
{
    data_type member1;
    data_type member2;
    .
    .
    data_type memeber;
};

What is Union?

The union is a user-defined data type which is used to store different data type in the same memory location.

Syntax

Union Syntax:
union union_name{

member defination;

member defination2;

......

member defination3;

}union variable;

Difference between Structure and Union

Below are the following point for structure

• Members of structure do not share memory. So A structure needs separate memory space for all its members i.e. all the members have unique storage.
• Members of structure can be accessed individually at any time.
• To define Structure, ‘struct’ keyword is used.
• All members of structure can be initialized.
• The size of the structure is > to the sum of each member’s size.
• Change in the value of one member can not affect the other in structure.

Below are the following point for union

• A union shares the memory space among its members so no need to allocate memory to all the members. Shared memory space is allocated i.e. equivalent to the size of a member having the largest memory.
• At a time, only one member of union can be accessed.
• To define Union, ‘union’ keyword is used.
• Only the first member of Union can be initialized.
• The size of union is equivalent to the size of the member having largest size.
• Change in the value of one member can affect the value of other member.

Still confused between structure and union feel free to comment, wer are here to help you.