c++ string转换大小写

#include
#include 
using namespace std;
int main()
{
    string s = "AakoOO";
    transform(s.begin(), s.end(), s.begin(), ::toupper);
    cout<<s<<endl;
    transform(s.begin(), s.end(), s.begin(), ::tolower);
    cout<<s<<endl;
    return 0;
}