STRUCTURES

STRUCTURES

            “Structure is a collection of non-homogeneous / heterogeneous / different data elements that can be grouped together under a common name”.

Structure Declaration and Definition

           

Syntax:           struct Tag

                                    {

                                                Datatype Member1;

                                                Datatype Member2;

                                                            - - -

                                                            - - -

                                                Datatype Membern;

                                    };

Ø  struct is a keyword used to define structure declaration.

Ø  Tag is name of the structure that follows same rules as a valid identifier.

Ø  Members declared inside the structure declaration are called structure elements (or) structure members.

Ø  Structure declaration must be ended with a semicolon.

Example:        struct Book

                        {

                                    char BName[50];

                                    int Pages;

                                    float Price;

                        };

Declaration of the structure does not reserve any storage space.  Memory is allocated only at the time of defining a structure variable. 

            Syntax:           struct Tag varname1, varname2, - - - - - , varnamep;

            Example:        struct Book B1,B2;

Now, the compiler allocates memory for B1 and B2 as:

i.e., Memory is allocated individually for each structure variable as well as individual memory area for each member of the structure.        

We have to create an object of structure to access its members. Object is a variable of type structure. Structure members are accessed using the dot operator(.) between structure's object and structure's member name.

Syntax :       struct struct_name var_name;

Example for creating object & accessing structure members

       #include<stdio.h>

       struct employee

       {

              int Id;

              char Name[25];

              long Salary;

       };

       void main()

       {

              struct employee E;            

                    printf("\nEnter Employee Id : ");

                    scanf("%d", &E.Id);

                    printf("\nEnter Employee Name : ");

                    scanf("%s", &E.Name);

                    printf("\nEnter Employee Salary : ");

                    scanf("%ld", &E.Salary);

                    printf("\n\n Employee Id : %d", E.Id);

                    printf("\n Employee Name : %s", E.Name);

                    printf("\n Employee Salary : %ld", E.Salary);

       }