C++ Structures

In C++, structures are used to group related data together to create a custom data type. Structures allow you to define your own data types with multiple members, making it easier to organize and manipulate complex data. In this article, we will explore the usage of structures in C++ with examples.

1. Defining Structures

To define a structure in C++, you use the struct keyword followed by the structure name and a list of member variables. Here's an example:

#include <iostream>

// Define a structure
struct Person {
    std::string name;
    int age;
    std::string address;
};

int main() {
    // Create a structure variable
    Person person1;

    // Access structure members
    person1.name = "John Doe";
    person1.age = 25;
    person1.address = "123 Main St";

    // Print structure members
    std::cout << "Name: " << person1.name << std::endl;
    std::cout << "Age: " << person1.age << std::endl;
    std::cout << "Address: " << person1.address << std::endl;

    return 0;
}

In the above code, we define a structure named Person with three member variables: name, age, and address. We then create a structure variable person1 and access its members using the dot operator (.). Finally, we print the structure members.

2. Initializing Structures

You can initialize structure variables at the time of declaration or later using the assignment operator. Here's an example:

#include <iostream>

struct Person {
    std::string name;
    int age;
    std::string address;
};

int main() {
    // Initialize structure at declaration
    Person person1 = {"John Doe", 25, "123 Main St"};

    // Initialize structure later
    Person person2;
    person2.name = "Alice Smith";
    person2.age = 30;
    person2.address = "456 Elm St";

    // Print structure members
    std::cout << "Name: " << person1.name << std::endl;
    std::cout << "Age: " << person1.age << std::endl;
    std::cout << "Address: " << person1.address << std::endl;

    std::cout << "Name: " << person2.name << std::endl;
    std::cout << "Age: " << person2.age << std::endl;
    std::cout << "Address: " << person2.address << std::endl;

    return 0;
}

In the above code, we demonstrate two ways to initialize structure variables. In the first method, we initialize person1 at the time of declaration using an initializer list. In the second method, we declare person2 and initialize its members separately using the assignment operator.

3. Passing Structures to Functions

You can pass structures to functions by value or by reference. Here's an example:

#include <iostream>

struct Person {
    std::string name;
    int age;
};

void printPerson(const Person& person) {
    std::cout << "Name: " << person.name << std::endl;
    std::cout << "Age: " << person.age << std::endl;
}

int main() {
    Person person = {"John Doe", 25};
    printPerson(person);

    return 0;
}

In the above code, we define a function printPerson that takes a constant reference to a Person structure. The function prints the name and age of the person. We pass the person variable to the function for printing.

Structures provide a convenient way to organize and manipulate related data in C++. They allow you to define custom data types with multiple members, making your code more structured and readable. Utilize structures to represent real-world entities and complex data structures effectively in your C++ programs.