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Go before initializing a variable causes a compiler error

Consider this code (VS2008):

void WordManager::formatWords(std::string const& document)
{
    document_ = document;
    unsigned int currentLineNo = 1;

    size_t oldEndOfLine = 0;
    size_t endOfLine    = document_.find('\n');
    while(endOfLine != std::string::npos)
    {
        std::string line = document_.substr(oldEndOfLine, (endOfLine - oldEndOfLine));
        if(line.size() < 2)
        {
            oldEndOfLine = endOfLine + 1;
            endOfLine    = document_.find('\n', oldEndOfLine);
            continue;
        }

        std::vector<std::string> words = Utility::split(line);
        for(unsigned int i(0); i < words.size(); ++i)
        {
            if(words[i].size() < 2)
                continue;
            Utility::trim(words[i], WordManager::delims);
            Utility::normalize(words[i], WordManager::replace, WordManager::replaceWith);

            if(ruleOne(words[i]) && ruleTwo(words[i]))
            {
                std::set<Word>::iterator sWIter(words_.find(Word(words[i])));

                if(sWIter == words_.end())
                    words_.insert(Word(words[i])).first->addLineNo(currentLineNo);
                else
                    sWIter->addLineNo(currentLineNo);
            }
        }
        ++currentLineNo;

        oldEndOfLine = endOfLine + 1;
        endOfLine    = document_.find('\n', oldEndOfLine);
    }
}

If this is important: this is the code from homework used to filter and change words in a document. documentcontains a document (previously read from a file)

I want to introduce a malicious goto, because I think it is actually cleaner in this case:

void WordManager::formatWords(std::string const& document)
{
    document_ = document;
    unsigned int currentLineNo = 1;

    size_t oldEndOfLine = 0;
    size_t endOfLine    = document_.find('\n');
    while(endOfLine != std::string::npos)
    {
        std::string line = document_.substr(oldEndOfLine, (endOfLine - oldEndOfLine));
        // HERE!!!!!!
        if(line.size() < 2)
            goto SkipAndRestart;

        std::vector<std::string> words = Utility::split(line);
        for(unsigned int i(0); i < words.size(); ++i)
        {
            if(words[i].size() < 2)
                continue;
            Utility::trim(words[i], WordManager::delims);
            Utility::normalize(words[i], WordManager::replace, WordManager::replaceWith);

            if(ruleOne(words[i]) && ruleTwo(words[i]))
            {
                std::set<Word>::iterator sWIter(words_.find(Word(words[i])));

                if(sWIter == words_.end())
                    words_.insert(Word(words[i])).first->addLineNo(currentLineNo);
                else
                    sWIter->addLineNo(currentLineNo);
            }
        }

SkipAndRestart:
        ++currentLineNo;

        oldEndOfLine = endOfLine + 1;
        endOfLine    = document_.find('\n', oldEndOfLine);
    }
}

Whether this is a good design choice doesn't matter at the moment. The compiler complainserror C2362: initialization of 'words' is skipped by 'goto SkipAndRestart'

I do not understand this error. Why is it important and a mistake that the initialization of words is skipped? This is exactly what I want, I don’t want him to do more work, just restarted the bloody cycle. Doesn't the continuation of the macro do more or less the same?

+7
source share
4

words:

    if(line.size() < 2)
        goto SkipAndRestart;
    std::vector<std::string> words = Utility::split(line);
    // ...
SkipAndRestart:

words SkipAndRestart:, . , words , , .

, words :

    if(line.size() < 2)
        goto SkipAndRestart;
    {
        std::vector<std::string> words = Utility::split(line);
        // ...
    }
SkipAndRestart:

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+17

goto :

std::vector<std::string> words = Utility::split(line);

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, , goto cleaner - , goto , , . , , goto - - goto.

+2

, - , goto , (inline) goto:

// Beware, brain-compiled code ahead!
inline void WordManager::giveThisAMeaningfulName(const std::string& word, std::string__size_type currentLineNo)
{
    Utility::trim(word, WordManager::delims);
    Utility::normalize(word, WordManager::replace, WordManager::replaceWith);
    if(ruleOne(word) && ruleTwo(word))
    {
        std::set<Word>::iterator sWIter(words_.find(Word(word)));
        if(sWIter == words_.end())
            words_.insert(Word(word)).first->addLineNo(currentLineNo);
        else
            sWIter->addLineNo(currentLineNo);
    }
}

void WordManager::formatWords(std::string const& document)
{
    document_ = document;
    std::string__size_type currentLineNo = 1;

    std::string line;
    while(std::getline(line))
        if(line.size() > 1)
        {
          std::vector<std::string> words = Utility::split(line);
          if(word.size() > 1)
              for(unsigned int i(0); i < words.size(); ++i)
                  giveThisAMeaningfulName(words[i], currentLineNo++);
        }
}

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, std::getline(), .

+1

'words' 'goto', 'if'.

// HERE!!!!!!
std::vector<std::string> words;
if(line.size() < 2)
     goto SkipAndRestart;
words = Utility::split(line);
0

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