Really quick silly question.

This is a discussion on Really quick silly question. within the C++ Programming forums, part of the General Programming Boards category; How do I parse a "? For example, I'm supposed to be coding a web crawler for this homework, and ...

  1. #1
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    Really quick silly question.

    How do I parse a "?

    For example, I'm supposed to be coding a web crawler for this homework, and hyperlinks are enclosed in quotes. How do I do a

    Code:
    string word;
    //code to fill in word
    
    if (word[i] == "\"") {
    //do stuff
    I'm getting a warning about converting between integers and pointers :\

  2. #2
    CSharpener vart's Avatar
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    word[i] is one char - it should be compared to one char '\"' and not a string
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  3. #3
    C++まいる!Cをこわせ! Elysia's Avatar
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    Double quotes -> string.
    Single quotes -> char.
    Strings must be compared using strcmp.
    Chars can be compared using regular comparison (==).
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

  4. #4
    CSharpener vart's Avatar
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    Strings must be compared using strcmp
    C-strings must be compared using strcmp
    std::strings should be compared using ==
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  5. #5
    C++まいる!Cをこわせ! Elysia's Avatar
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    Fair enough.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

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    Thanks, ' instead of " worked perfectly.

    Another question ><. How to easily transform strings into lowercase? I hear theres a function StringToLower, but I cant seem to get my program to recognize it. I also try word[i].tolower(), but its also recognized. Halp plz? Thanks ^_^.

  7. #7
    C++まいる!Cをこわせ! Elysia's Avatar
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    std::tolower.
    Member functions are only available on classes.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

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    Hrm, I'm missing something here. Its probably a preprocessor directive but the ones I'm finding on google arent doing me any good.

    I have:

    Code:
    string word = "Blah";
    word = tolower(word);
    Yet I receive a no matching function, candidates are INT tolower(INT).

    So how do I do this for strings @_@?

  9. #9
    C++まいる!Cをこわせ! Elysia's Avatar
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    Ah, it's only for characters... Hmm.
    The Standard Library really does not shine when it comes to this... And MSDN's docs sucks on the matter.
    Well, someone else should know.
    Last edited by Elysia; 04-03-2008 at 04:47 PM.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

  10. #10
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    Just loop through the word such as;
    Code:
               for (int a=0; a<word.length(); ++a)
                word[a]=tolower(word[a]);

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    Oh right, now that you told me how to use it, I can go back to my old loop. lol

    Thanks guys!

  12. #12
    C++まいる!Cをこわせ! Elysia's Avatar
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    Is this the quality of the standard library? Not even a function to make a lower case strings?
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

  13. #13
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    Quote Originally Posted by Elysia View Post
    Is this the quality of the standard library? Not even a function to make a lower case strings?
    Code:
    transform(source.begin(), source.end(), target.begin(),static_cast< int(*)(int) >(tolower));
    The STL was made to be generic. A single function just to transform strings to lower would be too specific. This unfortunately looks a little bad with the cast, but it's necessary because there are two tolower functions.
    It is too clear and so it is hard to see.
    A dunce once searched for fire with a lighted lantern.
    Had he known what fire was,
    He could have cooked his rice much sooner.

  14. #14
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    Ah ha, another questions ><. I'm trying to declare another in file stream, and its in a function outside of the main.

    Code:
    bool Crawl(blah) {
        ...
        for (int i = 0; i < hyperlinks.size(); i++) {
    	std::ifstream next_page(hyperlinks[i]);
    	if (next_page) {Crawl(web, next_page, hyperlinks[i]);}
    	next_page.close();
        }
        ...
    }
    It doesnt like this :\. No matching function calls again

  15. #15
    C++まいる!Cをこわせ! Elysia's Avatar
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    Is hyperlinks a vector of std::string?

    Quote Originally Posted by King Mir View Post
    Code:
    transform(source.begin(), source.end(), target.begin(),static_cast< int(*)(int) >(tolower));
    The STL was made to be generic. A single function just to transform strings to lower would be too specific. This unfortunately looks a little bad with the cast, but it's necessary because there are two tolower functions.
    Horrible solution to a fundamental problem IMO.
    Last edited by Elysia; 04-03-2008 at 06:39 PM.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

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