Pointer to Structure

A pointer to structure in C is a pointer variable that stores the memory address of a structure variable. Using this pointer, we can access the members of the structure indirectly using the -> (arrow) operator.

This is particularly useful when:

• Passing structures to functions efficiently.
• Dynamically allocating memory for structures.
• Handling arrays or linked lists of structures.

Why Use Pointer to Structure?

• Saves memory and improves performance when passing large structures to functions.
• Enables dynamic memory allocation of structures using malloc().
• Facilitates complex data structures like linked lists, trees, and graphs.

Syntax:

struct StructureName {
    data_type member1;
    data_type member2;
};

struct StructureName *ptr;

To point ptr to a structure variable:

ptr = &structure_variable;

Accessing Members Using Pointer:

• Use the arrow operator -> to access structure members via a pointer:

ptr->member1

Example: Pointer to Structure:

#include <stdio.h>
#include <string.h>

// Define a structure
struct Student {
    int roll;
    char name[50];
    float marks;
};

int main() {
    struct Student s1 = {101, "Ravi", 88.5};

    // Declare a pointer to the structure
    struct Student *ptr;

    // Assign address of s1 to pointer
    ptr = &s1;

    // Access members using pointer
    printf("Roll No: %d\n", ptr->roll);
    printf("Name: %s\n", ptr->name);
    printf("Marks: %.2f\n", ptr->marks);

    return 0;
}

Output:

Roll No: 101
Name: Ravi
Marks: 88.50