c++ - 如何提取 std::string c 的元素

Question

我有一个std::sting这样的：

std::string Str = "PARAM1;PARAM2;PARAM3;PARAM4"

我需要提取每个参数，例如：

char* param1 = explodStr[1] //return PARAM1 ...

我不熟悉 std::string，

谢谢你

Answer 1

我经常将此功能用于此类任务。它就像 PHP 的爆炸一样：

//------------------------------------------------------------------------------
// Name: explode
// Desc: Returns an array of strings, each of which is a substring of <s>
//       formed by splitting it on boundaries formed by the string <delimiter>.
//       (similar to PHP's explode)
//------------------------------------------------------------------------------
inline std::vector<std::string> explode(const std::string &delimeter, const std::string &s, int limit) {
    std::vector<std::string> results;

    if(!delimeter.empty()) {    

        std::string::size_type start = 0;
        std::string::size_type end   = s.find(delimeter, start);

        if(limit <= 0) {
            while(end != std::string::npos) {           
                results.push_back(s.substr(start, end - start));
                start = end + delimeter.size();
                end = s.find(delimeter, start);

                if(start == s.size() && end == std::string::npos) {
                    results.push_back(std::string());   
                }
            }
        } else if(limit > 0) {
            while(--limit > 0 && end != std::string::npos) {
                results.push_back(s.substr(start, end - start));
                start = end + delimeter.size();
                end = s.find(delimeter, start);

                if(start == s.size() && end == std::string::npos) {
                    results.push_back(std::string());   
                }
            }
        }

        if(start != s.size()) {
            results.push_back(s.substr(start)); 
        }

        while(limit++ < 0 && !results.empty()) {
            results.pop_back();
        }
    }

    return results;
}

或者没有限制：

//------------------------------------------------------------------------------
// Name: explode
// Desc: Returns an array of strings, each of which is a substring of <s>
//       formed by splitting it on boundaries formed by the string <delimiter>.
//       (similar to PHP's explode)
//------------------------------------------------------------------------------
inline std::vector<std::string> explode(const std::string &delimeter, const std::string &s) {
    return explode(delimeter, s, 0);
}

用法如下所示：

std::vector<std::string> x = explode(",", "THIS,IS,A,TEST");