在两个标签C / C ++之间获取子字符串

Question

Hello I am creating a parser of sorts in C/C++ it is rather simple i just want to be able to get a string from to tags "(" and ")" using C/C++ i know that the logic is like find first tag and increment a number every single char that is found until the next tag is found. But i suck a logic so if someone could at least give me a function that could help.

Edit:I see that C/C++ string functions are nothing alike so just C++ will do.

Answer 1

You seem unsure of the differences between string handling in C and in C++. Your description seems to imply wanting to do it in a C-style way.

void GetTag(const char *str, char *buffer)
{
    buffer[0] = '\0';
    char *y = &buffer[0];

    const char *x = &str[0];
    bool copy = false;

    while (x != NULL)
    {
        if (*x == '(')
            copy = true;
        else if (*x == ')' && copy)
        {
            *y = '\0';
            break;
        }
        else if (copy)
        { 
            *y = *x;
            y++;
        }
        ++x;
    }
}

Alternatively, the C++ way is to use the std::string which is safer because it's not fiddling with pointers, and arguably easier to read and understand.

std::string GetTag(const std::string &str)
{
    std::string::size_type start = str.find('(');
    if (start != str.npos)
    {
        std::string::size_type end = str.find(')', start + 1);
        if (end != str.npos)
        {
            ++start;
            std::string::size_type count = end - start;
            return str.substr(start, count);
        }
    }
    return "";
}