Nested Structure in C Programming

In this article, we discuss Nested Structures in C, a method to define a structure within another structure. Nested structures are useful when you want to logically group related data inside a larger structure.

Nested Structure in C Programming

What is Nested Structure in C?

A nested structure is a structure that contains another structure as a member. It allows you to organize complex data efficiently, especially when dealing with hierarchical or grouped data.

For example, if you want to store information about a student along with their address, you can create a structure for the address and nest it inside the student structure.

Syntax of Nested Structure

struct Outer {

    int id;

    char name[50];

    struct Inner {

        char street[50];

        char city[50];

        int zip;

    } address;

};

• Outer is the main structure.
• Inner is the nested structure representing the address.
• address is the variable of the nested structure inside Outer.

Example of Nested Structure

#include <stdio.h>

#include <string.h>

struct Address {

    char street[50];

    char city[50];

    int zip;

};

struct Student {

    int roll_no;

    char name[50];

    struct Address addr; // Nested structure

};

int main() {

    struct Student s1;

    s1.roll_no = 101;

    strcpy(s1.name, “Amit”);

    strcpy(s1.addr.street, “MG Road”);

    strcpy(s1.addr.city, “Pune”);

    s1.addr.zip = 411001;

    printf(“Student Roll No: %d\n”, s1.roll_no);

    printf(“Student Name: %s\n”, s1.name);

    printf(“Street: %s\n”, s1.addr.street);

    printf(“City: %s\n”, s1.addr.city);

    printf(“ZIP Code: %d\n”, s1.addr.zip);

    return 0;

}

Output:

Student Roll No: 101

Student Name: Amit

Street: MG Road

City: Pune

ZIP Code: 411001

How to Access Members of Nested Structure

• Use the dot (.) operator to access members of the outer structure.
• Use dot (.) operator again to access members of the nested structure.

Example: s1.addr.city accesses the city member inside the nested Address structure.

Advantages of Nested Structure

1. Organizes related data logically.
2. Simplifies handling of complex data records.
3. Makes code more readable and maintainable.
4. Reduces the need for multiple separate structures.

Disadvantages of Nested Structure

1. Accessing nested members can be verbose (outer.inner.member).
2. Increases memory usage if structures are large.
3. Requires careful memory management when used with pointers.

Use Cases of Nested Structures

• Storing student information along with address details.
• Managing employee records with department info.
• Representing hierarchical data like books in a library with publisher details.

Summary

Nested Structures in C allow you to create structured and organized data by embedding one structure inside another. This is useful for real-world applications where a single object has multiple attributes or related sub-objects.

POP- Introduction to Programming Using ‘C’

DS – Data structure Using C

OOP – Object Oriented Programming 

Java Programming

DBMS – Database Management System

RDBMS – Relational Database Management System