Structures allow users to define custom data types that group together variables of different types under a common name. Structures can contain arrays of other structures to create complex data structures. Nested structures contain structures within other structures, and can be defined separately or embedded within the containing structure. Pointers to structures allow structures to be passed to functions and their members accessed using the arrow operator.

2. CONTENTS :
 Introduction of structure
 Array of structure
 Nested structure
 Structure with pointer

3. Introduction -
In C/C++, struct keyword is used to define
a structure, a structure is the collection of
variables with a common name. Structure
variables are called fields. A structure is
heterogeneous in that it can be composed
of data of different types. Structure is an
user defined data type.

4.  Simple structure –
struct Structure_name{
datatype fieldname1;
datatype fieldname2;
………………………;
datatype fieldnamen;
};

8. The members of a structure are accessed with
the dot (.) operator.
syntax – structure_var_name.fieldname;
: st.rollno;
st.st_name;
st.per_marks;

10.  In contrast, array is homogeneous since it can
contain only data of the same type.
 Complex data structures can be formed by
defining arrays of structs.
syntax – struct structure_name array_name[i];
For Exa : struct student_type st[50];

12. Int main()
{
struct student st[50];
int I;
for(i=0;i<5;i++)
{

13. When a structure whose member also of a
structure type then such structure are called
Nested structure.
Nested are of two types –
1) Separate Structure
2) Embedded Structure
1) : We can create two
structures, but dependent
structure should be used inside the main
structure as a member.

14. struct date{
int dd;
int mm;
int yyyy;
}doj;
struct employee{
int id;
char name[20];
struct date doj;
}emp1;

15. 2) Embedded Structure : In this structure,
we can define structure
within the structure also.
struct employee{
int id;
char name[20];
struct date{
int dd;
int mm;
int yyyy;
}doj;
}emp1;

16. Structure with Pointer -
 Pointer variable can point to the address of a structure
variable.
For Exa – struct dog{
char name[10];
char breed[10];
int age;
char colour[10];
}spike;
struct dog my_dog={“tyke”,”Bulldog”, 5, “White”};
struct dog *ptr_dog;
ptr_dog=&spike;

17. When we want to access member of the
structure through pointer, arrow (->)
operator is used.
For Exa –
ptr_dog->name;
ptr_dog->breed;
Or –
(*ptr_dog).name;
(*ptr_dog).breed;

18.  For Exa –
struct point{
int x;
int y;
}point;
int main()
{
Point P;
printf(“Enter the coordinates of point”);
input(&P);
output(&P);
}

19. void input(point *point_ptr)
{
scanf(“%d”,&(point_ptr->x));
scanf(“%d”,&(point_ptr->y));
}
void output(point p)
{
printf(“x coordinate=%d”,p.x);
printf(“y coordinate=%d”,p.y);
}