Collection of heterogeneous data types are known as Structure.

Structure is one of the data types of C/C++ programming languages. Several data types are grouped together in structure.The basics of structure and the initialization process will be discussed in this part.

In C/C++ programming structure can be used. Its main goal is to group several heterogeneous data types. It can be stated as: 

• collection of heterogeneous data types which are grouped together
• referred as member: single unit of structure
• each member specified by: variable name + period (.) + member name
• definition specified by → "struct" keyword every structure  
• block definition is finished by a semicolon (;)

We want to build a structure based on company's employee information. Now for this the definition of structure will be: 

/* definition of structure & members declaration */
struct company{

	long int employee_id;

        int age;
	char sex;

	float salary;

};

/* definition of object of the following structure */

struct company employee;

storage_class struct user_defined_name{
	data_type  member 1;
        data_type  member 2;
	........
	data_type  member n;
};

(a) Graphical representation

(b) Symbolic representation  

Can be done by 2 ways:

1. Static initialization
2. External initialization

All the member values are assigned here.

A structure contains the information of employee_id, age, sex and salary. So, the structure looks like the followings:

struct company{

     long int employee_id;
     int age;

     char sex;

     float salary;

}employee;

Here "employee" is the variable tag. Initialization can be done one of the following ways:

employee.employee_id = 1000;

employee.age = 30;

employee.sex = 'M';

employee.salary = 30000;

OR

struct company employee2 = {1000, 32, 'F', 20000};

If any member is not initialized then that member is assigned with 0 values. For example, if the initialization is:

struct company employee = {1000};

Then, the members are initialized as follows:

employee.employee_id = 1000;

employee.age = 0;

mployee.sex = 0;

employee.salary = 0;

For this case, the entire member's values are assigned by the user. For the above structure, the values are collected from the user by the following way:

	cout << "ID     :"; cin >> employee.employee_id;
	cout << "Age    :"; cin >> employee.age;
	cout << "Sex    :"; cin >> employee.sex;
	cout << "Salary :"; cin >> employee.salary;