54filesi_o.cpp

#include <iostream>
#include <fstream>

/*
CLASSES TO USE WITH FILES IN C++

1) fstreambase
2) ifstream --> derived from fstreambase
3) ofstream --> derived from fstreambase
*/
using namespace std;

/*
In order to work with files in c++, you will have to open it. Primarily, there are 2 ways to open a file :

1) Using constructors
2) Using the member function open() of the class
*/
int main()
{
    // USING CONSTRUCTOR TO :
    // Write to a file
    string st1 = "This is a string";
    ofstream out("file.txt"); // since this is writing to a file, if the file doesn't exists it creates it with the same name
//    ^       ^      ^
//    |       |      |
// class  object  file name as an argument to constructor
    out << st1;
    // The object name can be anything
    out.close();
    // Reading to a file
    string st2;
    ifstream in("file.txt");
    in >> st2;
    cout << st2;

    // ofstream is used to write to file and ifstream is used to read the file

    //When we use cout and in for reading the file into a string, it treats the blank space or new line as end
    // for that to not happen, we use getline({{object}}, {{string}}) function

    for (int i = 0; i < 2; i++)
    {
        getline(in, st2);
        cout << st2<<endl;
    }
    // this reads the entire file.txt with spaces and new lines

    in.close();
    return 0;
}