Basic Input/Output in C++
- C++ I/O operation is using the stream concept.
- Stream is the sequence of bytes or flow of data.
- It makes the performance fast.
Output Stream/Operation:bytes/data flow from main memory to device like printer, display screen, or a network connection, etc,
Input Stream/Operation:bytes/data flow from device like printer, display screen, or a network connection, etc to main memory.
I/O Library Header Files
Let us see the common header files used in C++ programming are:
| Header File | Function and Description |
|---|---|
| It is used to define the cout, cin and cerr objects, which correspond to standard output stream, standard input stream and standard error stream, respectively. | |
| It is used to declare services useful for performing formatted I/O, such as setprecision and setw. | |
| 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
Let’s see the simple example of standard output stream (cout):
#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++ tutorialStandard 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.
Let’s see the simple example of standard input stream (cin):
#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.
Let’s see the simple example of standard end line (endl):
#include<iostream>
using namespace std;
int main( ) {
cout << “C++ Tutorial”;
cout << ” Welcome to”<<endl;
cout << “LetUsLearn”<<endl;
}
Output:
C++ Tutorial Welcome to
LetUsLearn