Structures (struct)

Structures (also called structs) are a way to group several related variables into one place.
Each variable in the structure is known as a member of the structure.
Unlike an array, a structure can contain many different data types (int, string, bool, etc.).
In C language we can only have data members in structures, we cannot have functions inside a structure.
In c++, structure can have data members as well functions inside the structure.
In c++, structure is much similar to a class (which will we study later).
To create a structure, use the struct keyword and declare each of its members inside curly braces

To access members of a structure, use the dot syntax (.):

// structures.cpp

// Define a structure named Rectangle (Named Structures)
struct Rectangle {

    // Data members
    int length;
    int width;

    // Member function to calculate the area of the rectangle
    int calculateArea() {
        return length * width;
    }
};

int main() {

    // Create an instance of the Rectangle structure
    Rectangle r1;

    // Assign values to the members of the structure
    r1.length = 5;
    r1.width = 10;

    // Access and print the area using the member function
    std::cout << "Rectangle area: " << r1.calculateArea() << endl;  // 50

    return 0;
}

In modern C++, you might also consider using classes instead of structures for more complex scenarios. Classes allow you to encapsulate data and behavior in a more object-oriented way.

Create a anonymous structure. In this way it makes hard to reuse the struct definition elsewhere in the code because it doesn't have a name.

struct {
    int myNum;
    string myString;
} myStructure;  // myStructure is instance not name of structure

// One Structure in Multiple Variables
struct {
int myNum;
string myString;
} myStruct1, myStruct2, myStruct3; // Multiple structure variables separated with commas

In structure, by default all data members and functions are public, they are accessible from outside
In class, by default all data members and functions are private. To make anything public, we have to write public.