/*
 * Reads standard input and outputs non-empty lines to standard output
 */

#ifndef __cplusplus
#error Please use a C++ compiler to build this application
#endif

#include <cstdlib>

#include <string>
#include <iostream>

using namespace std;

const string sSyntax =
    "Reads standard input and outputs the "
    "non-empty lines to standard output\n";

int main(int argc, const char *argv[])
{
    int iExitCode = EXIT_FAILURE;

    try
    {
	if (argc == 1)
	{
	    string line;
	    bool emptyLine = false;

	    cin.exceptions(istream::failbit | istream::badbit);
	    cout.exceptions(ostream::failbit | ostream::badbit | ostream::eofbit);
	    cout.sync_with_stdio(false);    // They say this might improve performace a bit

	    while (!cin.eof())
	    {
		getline(cin, line);

		string::iterator
		    lineEnd = line.end(),
		    lineBegin = line.begin();

		// Trime trailing spaces
		if (lineEnd != lineBegin)
		{
		    do
			lineEnd--;
		    while
			(
			    lineEnd != lineBegin
				&&
			    (
				*lineEnd == ' '
				    ||
				*lineEnd == '\r'
				    ||
				*lineEnd == '\n'
				    ||
				*lineEnd == '\t'
				    ||
				*lineEnd == '\f'
				    ||
				*lineEnd == '\v'
			    )
			);

		    if
			(
			    *lineEnd != ' '
				&&
			    *lineEnd != '\r'
				&&
			    *lineEnd != '\n'
				&&
			    *lineEnd != '\t'
				&&
			    *lineEnd != '\f'
				&&
			    *lineEnd != '\v'
			)
			    lineEnd++;

		    line.erase(lineEnd, line.end());
		}


		if (line.empty())
		    if (emptyLine)
			;   // An empty line has already been output
		    else
		    {
			cout << endl;
			emptyLine = true;
		    }
		else
		{
		    cout << line;
		    cout << endl;
		    emptyLine = false;
		}
	    }

	    iExitCode = EXIT_SUCCESS;
	}
	else
	    cout << sSyntax;
    }
    catch (ios_base::failure e)
    {
	cout << "Input/output error:\n";
	cout << e.what();
    }
    catch (exception e)
    {
	cout << "Error:\n";
	cout << e.what();
    }

    return iExitCode;
}