C++ 使用STL string 实现的split，trim，replace-修订

#include <iostream>
#include <vector>
using namespace std;

namespace strtool
{
string trim(const string& str)
{
string::size_type pos = str.find_first_not_of(' ');
if (pos == string::npos)
{
return str;
}
string::size_type pos2 = str.find_last_not_of(' ');
if (pos2 != string::npos)
{
return str.substr(pos, pos2 - pos + 1);
}
return str.substr(pos);
}

int split(const string& str, vector<string>& ret_, string sep = ",")
{
if (str.empty())
{
return 0;
}

string tmp;
string::size_type pos_begin = str.find_first_not_of(sep);
string::size_type comma_pos = 0;

while (pos_begin != string::npos)
{
comma_pos = str.find(sep, pos_begin);
if (comma_pos != string::npos)
{
tmp = str.substr(pos_begin, comma_pos - pos_begin);
pos_begin = comma_pos + sep.length();
}
else
{
tmp = str.substr(pos_begin);
pos_begin = comma_pos;
}

if (!tmp.empty())
{
ret_.push_back(tmp);
tmp.clear();
}
}
return 0;
}

string replace(const string& str, const string& src, const string& dest)
{
string ret;

string::size_type pos_begin = 0;
string::size_type pos       = str.find(src);
while (pos != string::npos)
{
cout <<"replacexxx:" << pos_begin <<" " << pos <<"\n";
ret.append(str.data() + pos_begin, pos - pos_begin);
ret += dest;
pos_begin = pos + 1;
pos       = str.find(src, pos_begin);
}
if (pos_begin < str.length())
{
ret.append(str.begin() + pos_begin, str.end());
}
return ret;
}

}

int main(int argc, char* argv[])
{
cout << strtool::trim(" nihao ") <<"\n";

vector<string> vt;
strtool::split(",o h,,,nice,,,,,,,", vt);
for (size_t i = 0; i < vt.size(); ++ i)
{
cout <<"out:" << vt[i] <<"\n";
}

string ret = strtool::replace("xxAxxxAxxAxx", "A", "B");
cout <<"replace:" << ret <<"\n";
return 0;
}