> ## Documentation Index
> Fetch the complete documentation index at: https://learn.acadlink.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Pointers and Structures

> Using pointers with structures and the arrow operator

# Pointer with Structure in C

A **pointer to a structure** stores the address of a structure variable. It allows you to access and modify structure members through the pointer using the **arrow operator** (`->`).

***

## Syntax

```c theme={null}
struct StructureName *pointer_name;
```

***

## Arrow Operator (`->`)

When accessing members through a pointer, use `->` instead of `.`:

```c theme={null}
ptr->member    // equivalent to: (*ptr).member
```

***

## Example: Pointer to Structure

```c theme={null}
#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;
}
```

**Output:**

```
Roll  = 101
Marks = 89.50
```

***

## Modifying Members via Pointer

```c theme={null}
#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
```

***

## Dot (`.`) vs Arrow (`->`)

| Situation                 | Operator | Example     |
| ------------------------- | -------- | ----------- |
| Direct structure variable | `.`      | `s1.roll`   |
| Pointer to structure      | `->`     | `ptr->roll` |

Both are equivalent:

```c theme={null}
ptr->roll     // using arrow
(*ptr).roll   // using dot after dereferencing — same thing
```

***

## Passing Structure Pointer to a Function

```c theme={null}
#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;
}
```

This is the preferred way to pass structures — no copying, direct modification possible.