C++ Files and Streams

In C++ programming we are using the iostream standard library, it provides cin and cout methods for reading from input and writing to output respectively.

To read and write from a file we are using the standard C++ library called fstream. Let us see the data types define in fstream library is:

---

Data Type	Description
fstream	It is used to create files, write information to files, and read information from files.
ifstream	It is used to read information from files.
ofstream	It is used to create files and write information to the files.

---

Write into a File

#include <iostream>  
#include <fstream>  
using namespace std;  
int main () {  
  ofstream filestream("testout.txt");  
  if (filestream.is_open())  
  {  
    filestream << "Welcome to NIIT.\n";  
    filestream << "C++ Tutorial.\n";  
    filestream.close();  
  }  
  else cout <<"File opening is fail.";  
  return 0;  
} 

Output

The content of a text file testout.txt is set with the data:
Welcome to javaTpoint.
C++ Tutorial.

---

Read From a file

    #include <iostream>  
    #include <fstream>  
    using namespace std;  
    int main () {  
      string srg;  
      ifstream filestream("testout.txt");  
      if (filestream.is_open())  
      {  
        while ( getline (filestream,srg) )  
        {  
          cout << srg <<endl;  
        }  
        filestream.close();  
      }  
      else {  
          cout << "File opening is fail."<<endl;   
        }  
      return 0;  
    }  

Output

Welcome to NIIT.
C++ Tutorial.