Structures in c++

As we are going to implement link list in our project, let us understand some basic concept
of structures in c++.
We often come around situations where we need to store a group of data whether of similar data types or non-similar data types.  Arrays in C++ which are used to store set of data of similar data types at contiguous memory locations.

                       Unlike Arrays, Structures in C++ are user defined data types which are used to store group of items of non-similar data types. A structure creates a data type that can be used to group items of possibly different types into a single type.                                            


 How to create a structure?

The ‘struct’ keyword is used to create a structure. The general syntax to create a structure is as shown below:

struct structureName

{ member1;

  member2;

  member3;

   .

   .

   .

   .

   .

   memberN;

};

Structures in C++ can contain two types of members:

• Data Member: These members are normal C++ variables. We can create a structure with variables of different data types in C++.
• Member Functions: These members are normal C++ functions. Along with variables, we can also include functions inside a structure declaration.

How to declare structure variables?
A structure variable can either be declared with structure declaration or as a separate declaration like basic types.

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; 

}

How to initialize structure members?

Structure members can be initialized using curly braces ‘{}’.

 For example,

struct Point 

{ 

int x, y; 

}; 

int main() 

{ 

struct Point p1 = {0, 1}; 

};

How to access structure elements?

Structure members are accessed using dot (.) operator.

#include <iostream> 

using namespace std; 

struct Point { 

int x, y; 

}; 

int main() 

{ 

struct Point p1 = { 0, 1 }; 

p1.x = 20; 

cout << "x = " << p1.x << ", y = " << p1.y; 

return 0; 

}

What is a structure pointer?

Like primitive types, we can have pointer to a structure. If we have a pointer to structure, members are accessed using arrow ( -> ) operator instead of the dot (.) operator.

#include <iostream> 

using namespace std; 

struct Point { 

int x, y; 

}; 

int main() 

{ 

struct Point p1 = { 1, 2 }; 

cout << p2->x << " " << p2->y; 

return 0; 

}