Nested structures or structures with structure in C

A structure with in a structure means nesting of structure. Nesting structure is permitted in C. let us consider the following structure where a employee structure is defined with in department structure.

Example:

struct department 

{

char name[20];

struct emp

{

 int id;

int salary;

char address[30];

}e;

}d;

The innermost member in a nested structure can be accessed as

d.e.id;

d.e.sal;

d.e.address;

We can also create nested  structures by using tag name that is one structure variable as a member of another structure.

Let us consider the following example where the structure variable of department structure us a member of employees structure 

Example:

struct department

{

char name[20];

int id;

}

struct employee

{

int salary;

struct department d;  // one structure variable as member of another structure member

}