[cs23021] appending to a file

[Mikhail Nesterenko]

CSI students,

As we discussed today. Ordinarily, if an existing file is opened for
writing, all its contents is overwritten. However, there is a way to
keep the existing contents and just append the new input to the
file. For that, open() function may take an additional argument called
mode. Mode "ios:app", means that the file is opened for writing with
appending. For example, the following code writes 0 1 2 3 4 to the
file.


#include <fstream>
using namespace std;

int main() {

    ofstream out_stream;

    for(int i=0; i < 5; i++){
    	    out_stream.open("outfile.txt", ios::app); 
	    out_stream << i << " ";
	    out_stream.close();
    }
}


Thanks,
-- 
Mikhail