Array of Structures and Structure within a Structure (Nested Structure) in C

Arrays of structures and nested structures provide a way to organize and manage complex data in C, allowing you to represent and work with more sophisticated data structures.

Let's explore examples of an array of structures and a structure within a structure (nested structure) in C.

1. Array of Structures:

In C, a structure is a user-defined data type that allows you to group together different types of variables under a single name. An array of structures is a collection of these structured data types arranged in a sequential manner. Each element of the array is an instance of the structure.

#include <stdio.h>

// Define a structure representing a point in 2D space
struct Point {
    int x;
    int y;
};

int main() {
    // Declare an array of structures
    struct Point points[3];

    // Initialize the array elements
    points[0].x = 1;
    points[0].y = 2;

    points[1].x = 3;
    points[1].y = 4;

    points[2].x = 5;
    points[2].y = 6;

    // Access and print the values
    for (int i = 0; i < 3; i++) {
        printf("Point %d: x = %d, y = %d\n", i + 1, points[i].x, points[i].y);
    }

    return 0;
}

In this example, we define a structure Point representing a point in 2D space. Then, we declare an array of Point structures and initialize its elements. The program prints the coordinates of each point in the array.

2. Structure within a Structure (Nested Structure):

A structure in C can contain members that are themselves structures. This concept is known as a nested structure. It allows you to model more complex relationships and represent hierarchical data structures.

#include <stdio.h>

// Define a structure representing a date
struct Date {
    int day;
    int month;
    int year;
};

// Define a structure representing a person
struct Person {
    char name[50];
    int age;
    struct Date birthdate; // Nested structure
};

int main() {
    // Declare a structure variable of type Person
    struct Person person1;

    // Initialize the values
    strcpy(person1.name, "John Doe");
    person1.age = 25;
    person1.birthdate.day = 15;
    person1.birthdate.month = 7;
    person1.birthdate.year = 1998;

    // Access and print the values
    printf("Person: %s, Age: %d\n", person1.name, person1.age);
    printf("Birthdate: %d-%d-%d\n", person1.birthdate.day, person1.birthdate.month, person1.birthdate.year);

    return 0;
}

In this example, we define two structures: Date for representing a date and Person for representing a person. The Person structure contains a nested structure (Date) to represent the birthdate. The program initializes a Person structure and prints the person's information, including the birthdate.

These examples illustrate how to work with arrays of structures and structures within structures in C.