Ι have a file called position.txt
which has been formatted in a particular fashion. This is the content of position.txt:
START POLYMER 1
1 0 0
2 0 0
3 0 0
4 0 0
4 1 0
5 1 0
5 0 0
6 0 0
END POLYMER 1
However, when I look at position.txt
using vi, I see this:
When I look at positions.txt
in sublime, I see:
Clearly, there seems to be an additional line added in Sublime, which is not even visible in Vi. This shouldn't be a problem, but I am running the following code:
int Grid::ExtractNumberOfPolymers(std::string filename){
std::regex start("START");
std::regex end ("END");
std::ifstream myfile (filename);
if ( !myfile ){
std::cerr << "File named " << filename << " could not be opened!" << std::endl;
exit(EXIT_FAILURE);
}
std::string myString;
// std::vector <std::string> StartContents;
// std::vector <std::string> EndContents;
int numberOfStarts {0}, numberOfEnds {0};
if (myfile.is_open() && !myfile.eof() ) {
while (myfile.good()) {
std::getline(myfile, myString); // pipe file's content into stream
if (std::regex_search(myString, start)){
numberOfStarts ;
}
else if (std::regex_search(myString, end)){
numberOfEnds ;
}
else if ( myString.empty()){
std::cerr << "ERROR: Empty line found. Bad positions file. " << std::endl;
exit (EXIT_FAILURE);
}
}
}
if (numberOfStarts==numberOfEnds){
return numberOfStarts;
}
else {
std::cerr << "Number of starts is not the same as number of ends. Bad input file." << std::endl;
return 0;
}
}
When I ran this code, I was exiting with the
std::cerr << "ERROR: Empty line found. Bad positions file. " << std::endl;
exit (EXIT_FAILURE);
error. I could not locate the error until I opened positions.txt and DELETING the final line. What is going wrong here? Why is Vim showing something like this?
I need the empty line error message because I do not want an interruption in the input file. I want coordinates at each line to not corrupt other parts of the code.
Any advice you have for me will be appreciated.
edit: using xxd on positions.txt, I get the following
[faraway_server] src $ xxd positions.txt
00000000: 5354 4152 5420 504f 4c59 4d45 5220 310a START POLYMER 1.
00000010: 3120 3020 3020 0a32 2030 2030 0a33 2030 1 0 0 .2 0 0.3 0
00000020: 2030 0a34 2030 2030 0a34 2031 2030 0a35 0.4 0 0.4 1 0.5
00000030: 2031 2030 0a35 2030 2030 200a 3620 3020 1 0.5 0 0 .6 0
00000040: 3020 0a45 4e44 2050 4f4c 594d 4552 2031 0 .END POLYMER 1
00000050: 0a
What should I do next?
CodePudding user response:
There is only one newline (\n
) after the last line with text so the fact that you read one empty line is due to a bug in your program.
This:
while (myfile.good()) {
std::getline(myfile, myString);
should be this:
while (std::getline(myfile, myString)) {
See Why is iostream::eof()
inside a loop condition (i.e. while (!stream.eof())
) considered wrong?