Pointers and Structures

For representing complex data structures, we can use structures and pointers together.

Pointer can be a member of structure, or a pointer to a structure, or an array of pointers to structure.

We can declare a pointer to structure as we do for pointers to basic data types.

Structure Syntax:

            struct structure_name

            {

                        datatype-1 variable-1;

                        datatype-2 variable-2;

                                    .

                                    .

                        datatype-n variable-n;

            }struct_variable, ponter-to-struct_variable;

Here, struct is a keyword which is used to define a structure template.

struct name is a name of the structure. It is user defined name.

The members of the structure are written in curly { } braces.

The structure is terminated by semicolon (;).

Structure to Pointer Example:

            struct student

            {

                        int rollno;

                        char name[50];

                        char branch[20];

                        float per;

            }s1, *sptr;

sptr = &s1;

Now, sptr points to s1 and can be used to access member variable of struct student.

To access member variables using pointer to structure, we have to use an arrow -> operator.

Syntax:

            struct_pointer -> member_variable;

Here, struct_pointer is a pointer to structure, and member_variable is the name of member variable.

Example:

            s1 -> rollno = 20;

We can also use dot (.) operator to access member variable with pointer to structure like:

            (*s1).rollno = 20;