I/O Library Header Files

              I/O Library Header Files

  

Header File	Description
<iostream>	It is used to define the cout, cin and cerr objects, which correspond to the standard output stream,standard input stream, and standard error stream, respectively.
<iomanip>	It is used to declare services useful for performing formatted I/O, such as setprecision and setw.
<fstream>	It is used to declare services for user-controlled file processing.

➤Standard output stream (cout).

The cout is a predefined object of ostream class. It is connected with the standard output device, which is usually a display screen. The cout is used in conjunction with stream insertion operator (<<) to display the output on a console.

Example:

#include <iostream>  

using namespace std;  

int main( ) 

{  

   char ary[] = "Welcome to C++ tutorial";  

   cout << "Value of ary is: " << ary << endl;  

}  

Output:Value of ary is: Welcome to C++ tutorial

➤Standard input stream (cin).

➡The cin is a predefined object of istream class. It is connected with the standard input device, which is usually a keyboard.

 ➡The cin is used in conjunction with stream extraction operator (>>) to read the input from a console.

Example:

#include <iostream>  

using namespace std;  

int main( ) 

{  

  int age;  

   cout << "Enter your age: ";  

   cin >> age;  

   cout << "Your age is: " << age << endl;  

}  

output:

Enter your age: 22

Your age is: 22

➤Standard end line (endl)

➡The endl is a predefined object of ostream class. It is used to insert a new line characters and flushes the stream.

Example:

#include <iostream>  

using namespace std;  

int main( ) {  

cout << " Tutorial";     

cout << " Best"<<endl;   

cout << "End of line"<<endl;   

} 

Output:

Tutorial Best

End of line