c++代码测试-std::string元素

//: c++代码测试
// std::string元素
std::string s = "mjk1MMM2122f999fg";
std::basic_string<char>::iterator it = s.begin();
locale loc;
for(; it != s.end(); it++){
if(isdigit(*it))
cout << *it;
else
if (::islower(*it))
cout << toupper(*it, loc);
else
cout << tolower(*it, loc);
}
cout << endl;