Diff inverter

diff_inverter.cpp

#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;

int main(int argc, char* argv[]) {
	ifstream file(argv[1]);
	string s;

	ostringstream sbuf;
	bool is_collect = false;

	while (getline(file, s)) {
		if (s[0] == '-' && (s.size() == 1 || s[1] == ' ')) {
			s[0] = '+';

			if (!is_collect) {
				is_collect = true;
				sbuf.str("");
			}
			sbuf << s << endl;
		} else if (s[0] == '+' && (s.size() == 1 || s[1] == ' ')) {
			s[0] = '-';
			cout << s << endl;
		} else {
			if (is_collect) {
				is_collect = false;
				cout << sbuf.str();
			}
			cout << s << endl;
		}
	}

	return EXIT_SUCCESS;
}