std::string 字符串切割

在很多字符串类库里都实现了split函数。不过在std里没有实现。在这里拿出几个：

1. 用单字符作为分隔

#include <string>
#include <vector>
using namespace std;
 
vector<string> split(string strtem,char a)
{
        vector<string> strvec;
 
        string::size_type pos1, pos2;
        pos2 = strtem.find(a);
        pos1 = 0;
        while (string::npos != pos2)
        {
                strvec.push_back(strtem.substr(pos1, pos2 - pos1));
 
                pos1 = pos2 + 1;
                pos2 = strtem.find(a, pos1);
        }
        strvec.push_back(strtem.substr(pos1));
        return strvec;
}

2. 由多个分隔符来分隔：

std::vector<std::string> splitString(std::string srcStr, std::string delimStr, bool repeatedCharIgnored)
{
    std::vector<std::string> resultStringVector;
    std::replace_if(srcStr.begin(), srcStr.end(),
        [&](const char& c){if (delimStr.find(c) != std::string::npos){ return true; } else{ return false; }}/*pred*/, delimStr.at(0));
    //将出现的所有分隔符都替换成为一个相同的字符（分隔符字符串的第一个）
    size_t pos = srcStr.find(delimStr.at(0));
    std::string addedString = "";
    while (pos != std::string::npos) {
        addedString = srcStr.substr(0, pos);
        if (!addedString.empty() || !repeatedCharIgnored) {
            resultStringVector.push_back(addedString);
        }
        srcStr.erase(srcStr.begin(), srcStr.begin() + pos + 1);
        pos = srcStr.find(delimStr.at(0));
    }
    addedString = srcStr;
    if (!addedString.empty() || !repeatedCharIgnored) {
        resultStringVector.push_back(addedString);
    }
    return resultStringVector;
}