//Knowledgedump.org - Function for adding line numbers to a .txt file. Writes to "filename_numbered.txt".

#ifndef ADD_LINE_NUMBERS_H		//Include guard
#define ADD_LINE_NUMBERS_H

#include <iostream>
#include <fstream>
#include <string>


int add_line_numbers(std::string filename) {			//Filename without .txt
	std::fstream stream;
	std::string str, full;
	int line_number = 1;

	//Read from text-file, save numbered content in string "full"
	stream.open(filename + ".txt", std::fstream::in);	//Open stream for reading of file
	if (stream.is_open()) {
		while (std::getline(stream, str)) {		//getline return interpreted as true, as long as it receives input
			full += std::to_string(line_number) + ": " + str + "\n";	//Numbering layout is 1: ... 2: ... etc.
			++line_number;
		}
		if(!full.empty()) full.pop_back();		//Remove extra '\n' character
		stream.close();
	}
	else {
		std::cout << "Couldn't open input filestream." << std::endl;
		return 0;
	}

	//Write to text-file "filename_numbered.txt"
	stream.open(filename + "_numbered.txt", std::fstream::out);
	if (stream.is_open()) {
		stream << full;
		stream.close();
	}
	else {
		std::cout << "Couldn't open output filestream." << std::endl;
	}
	return line_number - 1;		//Returns number of lines in text-file.
}



#endif		//Include guard

//Knowledgedump.org - Example file.

#include "add_line_numbers.h"

int main() {
	std::string input_txt = "test";
	//Add line numbers to text file "test" and print number of lines to console.
	std::cout << add_line_numbers(input_txt) << std::endl;
	return 0;
}

This
text
file


contains

several
lines

1: This
2: text
3: file
4: 
5: 
6: contains
7: 
8: several
9: lines