C++ I/O

Contents 1 File Output 2 File Input 2.1 Linewise 3 Directory Scanning

File Output

#include <fstream>
using namespace std;
...
ofstream file("test.txt");
file << "whatever";
file.close();

File Input

Linewise

#include <fstream>
using namespace std;
...
ifstream file("test.txt");
if(!file) throw Exception("Couldn't open file!");
string line;
while(!file.eof()) {
    getline(file, line);
    cout << "'" << line << "'" << endl;
}
file.close();

Directory Scanning

Output full pathname of all files in 'path' and subdirs:

// link with -lboost_filesystem
#include <boost/filesystem/operations.hpp>
#include <iostream>
using namespace boost::filesystem;
using namespace std;

class NoSuchPathException {};
void findFiles(const string& path) throw(NoSuchPathException) {

    if(!exists(path)) throw(NoSuchPathException());

    // for all dirs
    directory_iterator end_itr; // default construction yields past-the-end
    for(directory_iterator i(path); i != end_itr; ++i) {

        // if dir, recurse
        if(is_directory(*i)) findFiles(i->string());

        // output file name
        else cout << i->string();
    }
}