struct StructureName *pointer_name;

ptr->member    // equivalent to: (*ptr).member

#include <stdio.h>

struct Student {
    int roll;
    float marks;
};

int main() {
    struct Student s1 = {101, 89.5};
    struct Student *ptr;

    ptr = &s1;   // ptr holds the address of s1

    printf("Roll  = %d\n",   ptr->roll);
    printf("Marks = %.2f\n", ptr->marks);

    return 0;
}

Roll  = 101
Marks = 89.50

#include <stdio.h>

struct Student {
    int roll;
    float marks;
};

int main() {
    struct Student s1 = {101, 88.5};
    struct Student *ptr = &s1;

    ptr->marks = 95.0f;   // modify through pointer

    printf("Roll  = %d\n",   ptr->roll);
    printf("Marks = %.2f\n", ptr->marks);

    return 0;
}
// Output: Roll = 101  Marks = 95.00

ptr->roll     // using arrow
(*ptr).roll   // using dot after dereferencing — same thing

#include <stdio.h>

struct Student {
    int roll;
    float marks;
};

void display(struct Student *s) {
    printf("Roll : %d\n",   s->roll);
    printf("Marks: %.2f\n", s->marks);
}

int main() {
    struct Student s1 = {102, 91.5};
    display(&s1);
    return 0;
}