????string???????
string &operator+=(const string &s);//???????s????????????????尾
string &append(const char *s); //??c?????????s???????????????尾
string &append(const char *s??int n);//??c?????????s???n????????????????????尾
string &append(const string &s); //?operator+=()
string &append(const string &s??int pos??int n);//???????s?写?pos?????n?????????????????????尾
string &append(int n??char c); //???????????尾???n?????c
string &append(const_iterator first??const_iterator last);//???????first??last???????????????????????尾
????string?????
bool operator==(const string &s1??const string &s2)const;//??????????????????
?????">"??"<"??">="??"<="??"!="??????????????????????
int compare(const string &s) const;//????????????s???小
int compare(int pos?? int n??const string &s)const;//????????????pos?????n????????????????s???小
int compare(int pos?? int n??const string &s??int pos2??int n2)const;//????????????pos?????n????????????????s??
//pos2?????n2?????????????????小
int compare(const char *s) const;
int compare(int pos?? int n??const char *s) const;
int compare(int pos?? int n??const char *s?? int pos2) const;
compare??????>?????1??<?????-1??==?????0
????string???????
????string substr(int pos = 0??int n = npos) const;//????pos?????n??????????????
????string???????
????void swap(string &s2); //??????????????s2???
????string???????????
int find(char c?? int pos = 0) const;//??pos??????????c???????????位??
int find(const char *s?? int pos = 0) const;//??pos????????????s???????械?位??
int find(const char *s?? int pos?? int n) const;//??pos????????????s???n????????????械?位??
int find(const string &s?? int pos = 0) const;//??pos????????????s???????械?位??
//???????????????位?????????string::npos???
int rfind(char c?? int pos = npos) const;//??pos????????????????c???????械?位??
int rfind(const char *s?? int pos = npos) const;
int rfind(const char *s?? int pos?? int n = npos) const;
int rfind(const string &s??int pos = npos) const;
//??pos??????????????????s???n?????????????????????械?位??????????????位???????????string::npos???
int find_first_of(char c?? int pos = 0) const;//??pos??????????c????纬????位??
int find_first_of(const char *s?? int pos = 0) const;
int find_first_of(const char *s?? int pos?? int n) const;
int find_first_of(const string &s??int pos = 0) const;
//??pos????????????械??????s???n?????????????????????位?谩???????????string::npos
int find_first_not_of(char c?? int pos = 0) const;
int find_first_not_of(const char *s?? int pos = 0) const;
int find_first_not_of(const char *s?? int pos??int n) const;
int find_first_not_of(const string &s??int pos = 0) const;
//???????胁????????????s?械?????????位?????????string::npos
int find_last_of(char c?? int pos = npos) const;
int find_last_of(const char *s?? int pos = npos) const;
int find_last_of(const char *s?? int pos?? int n = npos) const;
int find_last_of(const string &s??int pos = npos) const;
int find_last_not_of(char c?? int pos = npos) const;
int find_last_not_of(const char *s?? int pos = npos) const;
int find_last_not_of(const char *s?? int pos?? int n) const;
int find_last_not_of(const string &s??int pos = npos) const;
//find_last_of??find_last_not_of??find_first_of??find_first_not_of?????????????????????
????string????婊�??????
string &replace(int p0?? int n0??const char *s);//?????p0?????n0????????????p0??????s
string &replace(int p0?? int n0??const char *s?? int n);//???p0?????n0????????????p0???????????s???n?????
string &replace(int p0?? int n0??const string &s);//?????p0?????n0????????????p0??????s
string &replace(int p0?? int n0??const string &s?? int pos?? int n);//???p0?????n0????????????p0??????s?写?pos?????n?????
string &replace(int p0?? int n0??int n?? char c);//???p0?????n0????????????p0??????n?????c
string &replace(iterator first0?? iterator last0??const char *s);//??[first0??last0??????????婊�??????s
string &replace(iterator first0?? iterator last0??const char *s?? int n);//??[first0??last0??????????婊�?s???n?????
string &replace(iterator first0?? iterator last0??const string &s);//??[first0??last0??????????婊�???s
string &replace(iterator first0?? iterator last0??int n?? char c);//??[first0??last0??????????婊�?n?????c
string &replace(iterator first0?? iterator last0??const_iterator first?? const_iterator last);//??[first0??last0??????????婊�??[first??last???????????