C Programming - Structures, Unions, Enums - Discussion

Both d.month and pdt->month will work fine.

Since d is a object of type struct date, we use '.' in d.month to access or modify value of month of object d.
whereas since pdt is pointer pointing to 'object d' we use pdt->month to access/modify the same.
Code below will print the same output regardless what operator you use.

Code:-
#include<stdio.h>
struct date
{
int day;
int month;
int year;
};

int main()
{
struct date d;
struct date *pdt;
pdt = &d;

pdt->month = 9;
printf("d.month = %d\n", d.month);
printf("pdt->month = %d\n", pdt->month);

d.month = 1;
printf("d.month = %d\n", d.month);
printf("pdt->month = %d\n", pdt->month);
return 0;
}

OUTPUT:-
d.month = 9
pdt->month = 9
d.month = 1
pdt->month = 1

Both d.month and pdt->month will work fine.

Since d is a object of type struct date, we use '.' in d.month to access or modify value of month of object d.
whereas since pdt is pointer pointing to 'object d' we use pdt->month to access/modify the same.
Code below will print the same output regardless what operator you use.

Code:-
#include<stdio.h>
struct date
{
int day;
int month;
int year;
};

int main()
{
struct date d;
struct date *pdt;
pdt = &d;

pdt->month = 9;
printf("d.month = %d\n", d.month);
printf("pdt->month = %d\n", pdt->month);

d.month = 1;
printf("d.month = %d\n", d.month);
printf("pdt->month = %d\n", pdt->month);
return 0;

OUTPUT:-
d.month = 9
pdt->month = 9
d.month = 1
pdt->month = 1

Hi Appu,
Here we are passing the address of d to pdt , and d is nothing but the object of the structure .pdt is pointer type so only -> opertaor is used to reference the member of the structure.

-> (direction operator or member selection via pointer operator).

Is used to access the members of the structure by its pointer variable (object of structure).

Plz, correct me for any mistake.

When we are using the pointer for pointing out the structure then we should use the arrow indicator instead of (.) operator.

'.' is also used used access the elements of a structure. Hence I think, both A and D are correct.

@All.

Here, It's told that assigning the value using 'pdt' variable.

So, option D is correct.

d.month=10;
printf("%d",d.month);

Output: 10
It is also correct. So, why only D ?

Here pdt pointer variable which is hold address of d so -> are used to access value.

If any one have any idea regarding this output of the program kindly give a comment.