c++ - 将带双引号的字符串替换为带双引号的字符串

Question

我正在编写这个软件，让我在我的网站上的工作更轻松一些。我只是输入了一个脚本，它会用 span 为我突出显示代码。它正在到达那里，但我有一个问题。 （我目前正在努力突出 UnityC#）

我希望字符串是黄色的，包括双引号，但我现在尝试它的方式会导致无限循环。我知道我对引号做错了什么，但我不知道那是什么。请帮帮我:)

变量original由std::string original ((istreambuf_iterator<char>(currentFile)), istreambuf_iterator<char>());创建，其中currentFile是我加载的脚本

std::size_t pos = 0;
while(original.find("\"", pos) != std::string::npos)
{
    //find the first occurrence of the quote
    std::size_t found = original.find("\"", pos);
    if(found != std::string::npos)
    {
        //save the start position of the string
        std::size_t start_pos = found;
        //save the end position by searching for the next quotation mark
        std::size_t end_pos = original.find_first_of("\"", start_pos+1);
        //Calculate the size of the string
        std::size_t length = end_pos-start_pos;
        //Make a copy of the word without the quotation marks
        std::string originalWord = original.substr(start_pos+1, length-1);
        //Make the new word with span, original word(without the quotation marks) and add quotation marks around the word
        std::string newWord = std::string("<span class='yellow_code'>") + "\"" + originalWord + "\"" + "</span>";
        std::cout<<originalWord<<" : "<<newWord<<std::endl;
        //Replace the string WITH the quotation marks for the newWord
        original.replace(start_pos, length+1, newWord);
        //Set the position to after the string
        pos = end_pos+1;
    }
    else
    {
        pos = found+1;
    }
}

当我运行它时，它将 cout: /dataValues.dat :​​ "/dataValues.dat" 无限。

怎么了？

问候， 丹妮

Answer 1

你应该std::regex

text = std::regex_replace(text,std::regex("string to be replaced"),"string with it earlier should be replaced");

Answer 2

问题出在这里：pos = end_pos + 1; 可以让你的索引在字符串之前比你的序言短。

让我们看看你的例子会发生什么：

• 原来original 是bla..."/dataValues.dat"... 而end_pos 是pos + 16
• 替换后你得到bla...<span class='yellow_code'>"/dataValues.dat"</span>... end_pos 没有改变，指向黄色的第一个l！
• 在下一次搜索中，您会再次找到相同的引号字符串...

您必须将<span...> 和</span> 的长度添加到end_pos 以使其紧跟在</span> 之后

Answer 3

您没有添加添加到字符串的开始和结束标记的大小。 这是一个如何做到这一点的示例

std::string start_tag = "<span class='yellow_code'>";
std::string end_tag = "\"</span>";

std::size_t pos = 0;
while(original.find("\"", pos) != std::string::npos)
{
    std::size_t found = original.find("\"", pos);
    if(found != std::string::npos)
    {
        std::size_t start_pos = found;
        std::size_t end_pos = original.find_first_of("\"", start_pos+1);
        if (end_pos == std::string::npos) // If the number of quotation characters is odd you would get undefined behavior
            break;
        std::size_t length = end_pos - start_pos;
        std::string originalWord = original.substr(start_pos+1, length-1);
        std::string newWord = start_tag + "\"" + originalWord + end_tag; // CHANGED: Added the start and end tags as std::string
        std::cout<<originalWord<<" : "<<newWord<<std::endl;
        original.replace(start_pos, length+1, newWord);
        pos = end_pos + start_tag.size() + end_tag.size(); // CHANGED: Added the size of the two tags
    }
}

更新

查看pos、found 和start_pos 之后，似乎其中两个是多余的。

std::size_t start_pos = 0;
while((start_pos = original.find("\"", start_pos)) != std::string::npos)
{
    std::size_t end_pos = original.find_first_of("\"", start_pos+1);
    if (end_pos == std::string::npos) // If the number of quotation characters is odd you would get undefined behavior
        break;
    std::size_t length = end_pos-start_pos;
    std::string originalWord = original.substr(start_pos+1, length-1);
    std::string newWord = start_tag + "\"" + originalWord + end_tag; // CHANGED: Added the start and end tags as std::string
    std::cout << originalWord << " : " << newWord <<std::endl;
    original.replace(start_pos, length+1, newWord);
    start_pos = end_pos + start_tag.size() + end_tag.size(); // CHANGED: Added the size of the two tags
}

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