string长度

void main()
{
 int nulsize = strlen("");//0
 std::string nulstr = "";
 nulsize = nulstr.size();//0
 char* hotitemBlob = new char[12];
 memset(hotitemBlob, 1, 12);
 char hotitemBlob2[12];
 unsigned int size1 = sizeof(hotitemBlob);//4
 unsigned int size2 = sizeof(hotitemBlob2);//12
 unsigned int size3 = sizeof(&hotitemBlob2);//4
}