Defining Structures in C++

Like arrays, structures are also used to store a list of data items in a single variable. However, these data items may be of different data types. Structures are used whenever a programmer requires binding the same or different types of related data items together into a single entity.

 A structure is defined as a collection of data items of either same or different data type referred to by a common name. The various data items of a structure are known as members (also known as elements or fields) of a structure.

Defining Structures

In order to use members of a structure in a program, a structure must be defined first. The definition of a structure informs the C++ compiler about the type and the number of the data members forming the structure. The syntax for defining a structure is

struct structure_name {
data_type member_name1;
data_type member_name2
};

To understand the concept of structure definition, consider this example.

Example: A code segment to demonstrate structure definition

struct sales_record {
  char grade;
  int item_code;
  int item_quantity;
  float item_rate;
};

In this example, a structure sales_record is defined with four members, namely, grade, item_code, item_quantity and item_rate. Note that the structure members are of different data types.

While defining a structure in C++, some important points should always be kept in mind.

• A structure member can have the same name as the name of the structure.

• Two members within a structure cannot have the same name. However, two members of different structures can have the same name.

• A structure cannot have the same name as the name of a variable defined outside the structure. However, a structure member can have the same name as the name of a variable defined outside the structure.

• A member of a structure cannot be initialized within the structure definition.