// Source: "Software Design ...", John A Robinson, Newnes, 2004, page 170.
//
// Add line numbers to a source code listing
// Prepend to each line a string: ' ',linenum in fixed width,": "
// To decide width of field, have to count the number of lines
//
// John Robinson 7 September 2003
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
int main(int argc, char *argv[]) {
	char linebuffer[2048];
	if (argc != 3) {
		cerr << "Usage: addnumbers in_codefile out_numbfile\n";
		return -1;
		}
	ifstream infile(argv[1]);
	if (!infile) {
		cerr << "Can't open " << argv[1] << endl;
		return -1;
		}
	// Count lines in infile
	int numlines = 0;
	while(!infile.eof()) {
		infile.getline(linebuffer, 2048);
		numlines++;
		}
	numlines--;		// Because last one was eof
	infile.clear();		// Clear eof flag
	infile.seekg(0);	// Rewind to start of infile
	// Work out field width for linenumbers
	int fieldwidth = 0;
	while (numlines) {
		fieldwidth++;
		numlines /= 10;
		}
	ofstream outfile(argv[2]);
	if (!outfile) {
		cerr << "Can't open " << argv[2] << endl;
		return -1;
		}
	int linenumber = 0;
	while(1) {	// Until we break out by finding end of file
		infile.getline(linebuffer, 2048);
		if (infile.eof())
			break;
		linenumber++;
		outfile << ' ' << setw(fieldwidth) << linenumber << ": ";
		outfile << linebuffer << endl;
		}
	infile.close();
	outfile.close();
	return 0;
	}