Explain pointer and structure with program and example

struct allowance
                     {
                        int basic_pay’
                         int da;
                         int hra;
                         int city_allowance;
                      };

struct employee
              {
                   char name[10];
                   char department[10];
                   struct allowance a1;
           }*ptr;
  ptr->name, ptr->department, ptr->a1.basic_pay, ptr->a1.da,
   ptr->a1.hra, ptr->a1.city_allowance
struct employee
{
  int eid;
 char name[10];
 char dept[10];
}emp[5],*ptr;
ptr=emp;
ptr->eid
ptr-->name
ptr->dept
for(ptr=emp;ptr<emp+5;ptr++)
printf(“%d%s%s”,ptr->eid,ptr->name,ptr->dept);

We could also use the notation :
(*ptr).eid
(*ptr).name
(*ptr).dept

The operators  ->, . , ( ), [ ] enjoy the highest priority among the operators.
struct
{
   int count;
    float *p;
  } *ptr;
  ++ptr->count;
Increments the count not ptr, however
(++ptr)->count;
First increments the ptr then links count.

struct employee
{
    int eid;
    char name[10];
    char dept[10];
 } emp,*ptr;

Using dot operator : emp.eid, emp.name, emp.dept
Using indirection : (*ptr).eid, (*ptr).name, (*ptr).dept
Using selection notation : ptr->eid, ptr->name, ptr->dept