Estructuras en C++

A menudo nos encontramos con situaciones en las que necesitamos almacenar un grupo de datos, ya sea de tipos de datos similares o tipos de datos no similares. Hemos visto arrays en C++ que se utilizan para almacenar conjuntos de datos de tipos de datos similares en ubicaciones de memoria contiguas.
A diferencia de las arrays, las estructuras en C++ son tipos de datos definidos por el usuario que se utilizan para almacenar grupos de elementos de tipos de datos no similares. 

¿Qué es una estructura?

// Data Members
int roll;
int age;
int marks;
     
// Member Functions
void printDetails()
{
    cout<<"Roll = "<<roll<<"\n";
    cout<<"Age = "<<age<<"\n";
    cout<<"Marks = "<<marks;
}

// A variable declaration with structure declaration.
struct Point
{
   int x, y;
} p1;  // The variable p1 is declared with 'Point'
 
 
// A variable declaration like basic data types
struct Point
{
   int x, y;
};
 
int main()
{
   struct Point p1;  // The variable p1 is declared like a normal variable
}

struct Point
{
   int x = 0;  // COMPILER ERROR:  cannot initialize members here
   int y = 0;  // COMPILER ERROR:  cannot initialize members here
};

// In C++ We can Initialize the Variables with Declaration in Structure.
 
#include <iostream>
using namespace std;
 
struct Point {
    int x = 0; // It is Considered as Default Arguments and no Error is Raised
    int y = 1;
};
 
int main()
{
    struct Point p1;
 
    // Accessing members of point p1
    // No value is Initialized then the default value is considered. ie x=0 and y=1;
    cout << "x = " << p1.x << ", y = " << p1.y<<endl;
   
    // Initializing the value of y = 20;
    p1.y = 20;
    cout << "x = " << p1.x << ", y = " << p1.y;
    return 0;
}
// This code is contributed by Samyak Jain

struct Point {
    int x, y;
};
 
int main()
{
    // A valid initialization. member x gets value 0 and y
    // gets value 1.  The order of declaration is followed.
    struct Point p1 = { 0, 1 };
}

#include <iostream>
using namespace std;
 
struct Point {
    int x, y;
};
 
int main()
{
    struct Point p1 = { 0, 1 };
 
    // Accessing members of point p1
    p1.x = 20;
    cout << "x = " << p1.x << ", y = " << p1.y;
 
    return 0;
}

#include <iostream>
using namespace std;
 
struct Point {
    int x, y;
};
 
int main()
{
    // Create an array of structures
    struct Point arr[10];
 
    // Access array members
    arr[0].x = 10;
    arr[0].y = 20;
 
    cout << arr[0].x << " " << arr[0].y;
    return 0;
}

#include <iostream>
using namespace std;
 
struct Point {
    int x, y;
};
 
int main()
{
    struct Point p1 = { 1, 2 };
 
    // p2 is a pointer to structure p1
    struct Point* p2 = &p1;
 
    // Accessing structure members using
    // structure pointer
    cout << p2->x << " " << p2->y;
    return 0;
}