C++ File and Stream

by Online Tutorials Library July 14, 2022

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.

C++ FileStream example: writing to a file

Let’s see the simple example of writing to a text file testout.txt using C++ FileStream programming.

 #include <iostream> #include <fstream> using namespace std; int main () {   ofstream filestream(“testout.txt”);   if (filestream.is_open())   {     filestream << “Welcome to Tutor Aspire.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 Tutor Aspire. C++ Tutorial.

C++ FileStream example: reading from a file

Let’s see the simple example of reading from a text file testout.txt using C++ FileStream programming.

 #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; } 

Note: Before running the code a text file named as “testout.txt” is need to be created and the content of a text file is given below:
Welcome to Tutor Aspire.
C++ Tutorial.

Output:

Welcome to Tutor Aspire. C++ Tutorial.

C++ Read and Write Example

Let’s see the simple example of writing the data to a text file testout.txt and then reading the data from the file using C++ FileStream programming.

 #include <fstream> #include <iostream> using namespace std; int main () {    char input[75];    ofstream os;    os.open(“testout.txt”);    cout <<“Writing to a text file:” << endl;    cout << “Please Enter your name: “;     cin.getline(input, 100);    os << input << endl;    cout << “Please Enter your age: “;     cin >> input;    cin.ignore();    os << input << endl;    os.close();    ifstream is;     string line;    is.open(“testout.txt”);     cout << “Reading from a text file:” << endl;     while (getline (is,line))    {    cout << line << endl;    }    is.close();    return 0; } 

Output:

Writing to a text file:    Please Enter your name: Nakul Jain     Please Enter your age: 22    Reading from a text file:   Nakul Jain    22

Next TopicC++ getline()

C++ File and Stream

C++ Files and Streams

C++ FileStream example: writing to a file

C++ FileStream example: reading from a file

Note: Before running the code a text file named as “testout.txt” is need to be created and the content of a text file is given below: Welcome to Tutor Aspire. C++ Tutorial.

C++ Read and Write Example

Array of sets in C++

C++ Program to Convert Number in Character

You may also like

Note: Before running the code a text file named as “testout.txt” is need to be created and the content of a text file is given below:
Welcome to Tutor Aspire.
C++ Tutorial.