[jaeusm]

#include <sstream>
#include <fstream>
#include <string>
using namespace std;

string itos(int i){
	stringstream s;
	s << i;
	return s.str();
}

int main(){
	string fname = "file", ext = ".txt";
	int someNum = 10;
	for (int i=0; i<someNum; i++){
		fname += itos(i) + ext;
		ofstream out(fname.c_str());
		out.close();
		fname = fname.substr(0,4);
	}
		  
	return 0;
}

This works, but it's pointless.