C Programming language

Introduction of C structure

In some programming contexts, you need to access multiple data types under asingle name for easy manipulation; for example you want to refer to address with multiple data like house number, street, zip code, country C supports structure which allows you to wrap one or more variables with different data types. A structure can contain any valid data types like int, char, float even arrays and other structures. Each variable in structure is called a structure member.

Defining structure

To define a structure, you can use struct keyword.

struct struct_name{ structure_member };

The name of structure is followed the rule of variable name.

For example

1. struct address{ 
2. unsigned int house_number; 
3. char street_name[50]; 
4. int zip_code; 
5. char country[50]; 
6. };

It contains house number as an positive integer, street name as a string, zip code as an integer and country as a string.

Declaring structure

The above example only defines an address structure without create any instance of it. To create or declare a structure you have two ways:

The first way is declare a structure follows by structure definition like this :

struct struct_name { structure_member; ... }

instance_1,instance_2 instance_n; 

In the second way you can declare your structure instance at a different location in your source code after structure definition.

Here is structure declaration syntax :

struct struct_name instance_1,instance_2 instance_n; 

Complex structure

Structure can contains arrays or other structures so it is sometimes called complex structure.

For example address structure is a complex structure. We can define a complex structure which contains address structure as follows:

 struct customer{ 
char name[50]; 
structure address billing_addr;
 
 structure address shipping_addr; 5. };