Accessing data from file - c++

Question

I'm aware this has been discussed a lot on SO (and elsewhere). I'm resorting to asking here as I'm still stuck. Maybe I'm doing something really brainless/silly or maybe it's a genuine gotcha...
I have a directory of files, each with the extension '.pts' - opening one reveals:
version: 1
n_points: 68
{
498.801220 504.771171
516.076459 571.681686
518.038170 628.516761
...
Pasting here gets the formatting wrong a little, so be advised that there is no empty line between each line of data. There are also 68 of these float pairs, however I omit them here.
Eventually I want a vector of the pairs as rounded shorts - e.g. 499, 505, 516, 572, 518, 629 ...
But at the moment I can't access the floats as is, let alone any information.
The code so far:
#include <iostream>
#include <string>
#include "dirent.h"
#include <fstream>
#include <sstream>
#include <stdio.h>
using namespace std;
bool has_suffix(const string& s, const string& suffix)
{
return (s.size() >= suffix.size()) && equal(suffix.rbegin(), suffix.rend(), s.rbegin());
}
int main(int argc, char **argv)
{
string path = "C:\\testset";
DIR *dir = opendir(path.c_str());
if(!dir)
{
return 1;
}
dirent *entry;
string fileName;
float number;
string dummy;
while(entry = readdir(dir))
{
if(has_suffix(entry->d_name, ".pts"))
{
fileName = entry->d_name;
fileName = path + "\\" + fileName; // <<added at suggestion of Martin James
//Working up to here as I see all the .pts files listed when I print them:
cout << fileName << endl;
ifstream file(fileName, std::ios_base::in);
//however from here:
while (file >> number)
{
//...nothing will print
printf("%f ", number);
}
file.close();
}
}
closedir(dir);
}
Finding all the .pts files is working (thanks other thread on SO :) - and they do appear to be simple .text files as they open in text editors. There is a 'LF' at the end of each line.
Problem is that running the code will only result in the file names being listed. It seems that "while (file >> number)" isn't returning anything to run the print statement. Thing is, other threads on the topic indicate (at least to me) that it is as simple as this.
I feel it's likely that the answer will involve things I've looked at in the last few hours - dummy string variables to soak up all the stuff at the top of the file I don't need? getline? 'tokens'? I would show you all my attempts at nutting it out but I don't want to bog down the question:
Given a txt file formatted like above how would you access the values from line 4 onwards?
Any help greatly appreciated :)

Answer 1

The problem here is that, you are not reading in the header information. The >> operation fails, because you are trying to read in the string "version: 1" as a float.
To fix this, you should either skip the header with few calls to std::getline or parse it to get information about the contents.
Edit: To skip the lines you can just do:
for(int i=0;i<3;i++) //Skip header
std::getline(file,dummy);