Introduction
As C++ features the real world model so at times it
becomes necessary for the programmer to store a number of information about a
particular object in C++ .Here we make use of the structures in C++.like for
storing the roll number, name and class of many students we have to take
different variables which will become very difficult if the number of students
are more say 50 or 100.so here we make use of structure which can store the
different information about an object under a common name. It is better to use
a common name for every student rather than using variable for each entity of a
student.
structure
So structure is basically the grouping of variables
under a common name. Structure is declared using the keyword struct.Yes you are
right a structure needs to be declared before it can be used in C++.take a look
at the syntax of a structure
struct structure
name {
Datatype member 1 name;
Datatype member n name;
};
Example:
struct student
{
int roll;
char name[40];
};
Making
structure variable
In order
to use a structure we need to make structure variable after which we can store
data in the structure variable. The variable is created in the following
way.
Structure
name variable name;
A member of
a structure is the variable declared inside the structure body we will refer to
them as member variables and the structure object as the structure variable. A
member variable is accessed using the dot (.) operator. That means to access or
use the member roll of the structure student we use the command
student.roll=15;
These members along with their full address i.e. the way I
have explained above can be used as any other variable. An able programmer can
use this feature by looping and playing with the name using arrays..
One full example showing all the features of the structure
concept
#include<iostream.h>
struct stud
{
int roll;
char div;
};
void main()
{
stud a,b,c;
cout<<"enter
the details for first student\n";
cout<<"enter
the roll number:";
cin>>a.roll;
cout<<"enter
the division:";
cin>>a.div;
cout<<"enter
the details for second student\n";
cout<<"enter
the roll number:";
cin>>b.roll;
cout<<"enter
the division:";
cin>>b.div;
cout<<"enter
the details for third student\n";
cout<<"enter
the roll number:";
cin>>c.roll;
cout<<"enter
the division:";
cin>>c.div;
cout<<"\nthe details are as follows \n";
cout<<"the
first student\n";
cout<<"roll
number:"<<a.roll;
cout<<"\ndivision:"<<a.div;
cout<<"\nthe second student\n";
cout<<"roll
number:"<<b.roll;
cout<<"\ndivision:"<<b.div;
cout<<"\nthe third student\n";
cout<<"roll
number:"<<c.roll;
cout<<"\ndivision:"<<c.div;
}
