Comparing std::string
-s like that will work. However you are comparing string literals. To do the comparison you want either initialize a std::string with them or use strcmp:
if(std::string("aa") > std::string("bz")) cout<<"Yes";
This is the c++ style solution to that.
Or alternatively:
if(strcmp("aa", "bz") > 0) cout<<"Yes";
EDIT(thanks to Konrad Rudolph’s comment): in fact in the first version only one of the operands should be converted explicitly so:
if(std::string("aa") > "bz") cout<<"Yes";
Will again work as expected.
EDIT(thanks to churill’s comment): since c++14 you can use string literals:
if("aa"s > "bz") cout<<"Yes";