Problems stripping comments

This is a discussion on Problems stripping comments within the C++ Programming forums, part of the General Programming Boards category; I'm trying to strip the code of all comments. However, as you can see, it doesn't work right. Anyone know ...

  1. #1
    The Defective GRAPE Lurker's Avatar
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    Problems stripping comments

    I'm trying to strip the code of all comments. However, as you can see, it doesn't work right. Anyone know the problem?

    Code:
    #include <iostream>
    #include <fstream>
    #include <string>
    using namespace std;
    
    int main() {
    	string str = "", main = "";
    	ifstream in("file.txt");
    	int pos;
    	while(!in.eof()) {
    		in.getline((char *) str.c_str(), 255);
    		pos = str.find("//");
    		if(pos != string.npos) {
    			main += str.erase(pos, str.length());
    		} else {
    			main += str;
    		}
    		main += '\n';
    	}
    	cout << main << endl;
    	in.close();
    	cin.get();
    	return 0;
    }
    I'm running it with this as file.txt:
    Code:
      one; // comment 1
    		two;
    
    
    
    
    
    r;
    four;
    Do not make direct eye contact with me.

  2. #2
    Registered User
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    try changing this:
    main += str.erase(pos, str.length());

    to this:
    str.erase(pos, str.end());
    main += str;

    As far as I can tell string::erase() takes either a single iterator or a range of iterators. even if it took a starting position and the number of char to erase (which is what I think you are trying to do), you probably don't want to erase the entire length of str as you will go out of bounds unless pos == str.begin().

  3. #3
    The Defective GRAPE Lurker's Avatar
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    How do I get an iterator to the posth position?
    Do not make direct eye contact with me.

  4. #4
    Registered User jlou's Avatar
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    Quote Originally Posted by Lurker
    Code:
    in.getline((char *) str.c_str(), 255);


    It should probably be
    Code:
    getline(in, str);
    also:
    Quote Originally Posted by Lurker
    Code:
    pos = str.find("//");
    if(pos != string.npos) {
    	main += str.erase(pos, str.length());
    } else {
    	main += str;
    }
    should be
    Code:
    main += str.substr(0, str.find("//"));

  5. #5
    The Defective GRAPE Lurker's Avatar
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    Great! Thanks for all the help!
    Do not make direct eye contact with me.

  6. #6
    Registered User major_small's Avatar
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    what about the /**/ comments
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