=====I/O Constructors=====
Syntax:

<code>
    #include <fstream>
    fstream( const char *filename, openmode mode );
    ifstream( const char *filename, openmode mode );
    ofstream( const char *filename, openmode mode );
</code>

The fstream, ifstream, and ofstream objects are used to do file I/O. The
optional mode defines how the file is to be opened, according to the [[io/io_flags#mode_flags|IO stream
mode flags]]. The optional filename specifies the file to be opened and
associated with the stream.

Input and output file streams can be used in a similar manner to C++ predefined
I/O streams, cin and cout.

For example, the following code reads input data and appends the result to an output file.

<code>
    ifstream fin( "/tmp/data.txt" );
    ofstream fout( "/tmp/results.txt", ios::app );
    while( fin >> temp )
      fout << temp + 2 << endl;
    // Files are closed automatically when the variables fin and fout fall out of scope.
</code>

Related Topics: [[close]], [[open]]