C++ Program 3

A Program to view the use of 'cout & cin' objects :-

#include<iostream.h>
#include<conio.h>
void main()

{
clrscr();
int a;
cout<<"Enter a number:";
cin>>a;
cout<<"You are the best student:"<<a;
getch();
}

Output:

Enter a number:6
You are the best student:6

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In C++ articles, these two keywords cout and cin are used very often for taking inputs and printing outputs. These two are the most basic methods of taking input and output in C++. For using cin and cout we must include the header file iostream in our program.

In this article we will mainly discuss about the objects defined in the header file iostream like cin and cout.

Standard output stream (cout): Usually the standard output device is the display screen. cout is the instance of the ostream class. cout is used to produce output on the standard output device which is usually the display screen. The data needed to be displayed on the screen is inserted in the standard output stream (cout) using the insertion operator (<<).

#include<iostream>
using namespace std;

int main( ) {
char sample[] = "MayankRana";

cout << sample << " - I created the DreamStudy website";

return 0;
}

Output
MayankRana - I created the DreamStudy website

As you can see in the above program the insertion operator(<<) insert the value of the string variable sample followed by the string “A computer science portal for geeks” in the standard output stream cout which is then displayed on screen.

standard input stream (cin): Usually the input device is the keyboard. cin is the instance of the class istream and is used to read input from the standard input device which is usually keyboard.
The extraction operator( >> ) is used along with the object cin for reading inputs. The extraction operator extracts the data from the object cin which is entered using the keboard.

Example:-
#include<iostream>
using namespace std;
int main()
{
int age;

cout << "Enter your age:";
cin >> age;
cout << "\nYour age is: "<<age;

return 0;
}

Input :- 18

Output:
Enter your age:-
Your age is: 18

The above program asks the user to input the age. The object cin is connected to the input device. The age entered by the user is extracted from cin using the extraction operator( >> ) and the extracted data is then stored in the variable age present on the right side of the extraction operator.