Creating a File Parser in C++

Question

I am trying to create a parser class that will parse a file based on " " and place the words into a linked list.

class FileReader { public: FileReader(char* file) { ifstream fout (file, ifstream::in); string hold; while (fout.good()) { getline (fout, hold, " "); cout << hold; } fout.close(); } };

The function getline(fout, hold, " ") is not recognizing " " as the delimiter.

I have not coded the linked list part as of yet so this is just the parsing part of the program.

Also would there be a better way to create a parser?

If regex is an option, this might help: criticalindirection.com/2016/01/05/… — user31986
– user31986, Commented Jan 5, 2016 at 11:45

Kerrek SB · Accepted Answer · 2013-10-03 21:19:23Z

3

It should just work like this:

#include <fstream> #include <iterator> #include <list> #include <string> std::ifstream infile(file); std::list<std::string> words(std::istream_iterator<std::string>(infile), std::istream_iterator<std::string>());

Now words is your linked list of whitespace-separated tokens.

Lesson: The best kind of code is the one you don't have to write.

answered Oct 3, 2013 at 21:19

Kerrek SB

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4 Comments

Kerrek SB Over a year ago

@user814628: You were prepared to use std::getline, so... small difference.

Zac Howland Over a year ago

@user814628 No sense in rewriting code when code to do the same task is already written and well-tested.

goji Over a year ago

It's very easy to overlook some of the nifty features in the standard library ... ;)

dchhetri Over a year ago

@KerrekSB judging from OP's code, it doesn't seem like he is at level where he would understand what exactly are those lines of code doing. I just posted a simple solution to which I believe he could grasp at this point more easily.However, I did fail to mention better solutions, to which you have provided. Thanks.

dchhetri · Accepted Answer · 2013-10-03 21:45:59Z

2

The last parameter in getline is a char not a string. Looking at your current code, you want getline(fout,hold,' ') or just getline(fout,hold) -- *if you want the whole line.

*: edit

edited Oct 3, 2013 at 21:45

answered Oct 3, 2013 at 21:20

dchhetri

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1 Comment

Zac Howland Over a year ago

getline(fout, hold) will get an entire line ... not just individual words.

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