#include <iostream>   //C++ example
#include <fstream>
#include <cstdlib>
using namespace std;

int main(int argc, char **argv)
{
	fstream fstr("file", ios_base::in | ios_base::out | ios_base::trunc);
	if (!fstr) {
		cerr << "can't open file.\n";
		return EXIT_FAILURE;
	}

	fstr << "hello";   //Output five characters.

	cout << "input position == " << fstr.tellg() << "\n";
	if (!fstr) {
		cerr << "can't tellg.\n";
		return EXIT_FAILURE;
	}

	fstr.seekg(0);
	if (!fstr) {
		cerr << "can't seekg.\n";
		return EXIT_FAILURE;
	}

	cout << "input position == " << fstr.tellg() << "\n";
	if (!fstr) {
		cerr << "can't tellg.\n";
		return EXIT_FAILURE;
	}

	char buffer[256];   //uninitialized variable
	fstr >> buffer;

	cout << buffer << "\n";
	return EXIT_SUCCESS;
}