c - Declaring inner structure variable in nested structure without referring outer structure -

i creating simple nested structure aware it's functioning process.here example:

struct employee {    char ename[20];    int ssn;    float salary;    struct date        {        int date;        int month;        int year;         }doj; }emp1; 

in case if want access members of inner structure need like

emp1.doj.date = 10; 

but in above structure if omit variable declaration of structure date i.e doj , try declare separately it did not require reference emp1 i.e

struct date doj; 

the compiler did not give error in case. can access members of structure date without reference emp1 like

doj.date =15; 

i want know how possible?

there no special scoping rules inner structures in c means scope of struct date same scope of struct employee. free declare objects of inner structure type anywhere can declare object of outer structure type.

for example, these declarations same yours:

struct date {     int date;     int month;     int year;  };  struct employee {    char ename[20];    int ssn;    float salary;    struct date doj; }emp1;