摘要：
string substr (size_t pos = 0, size_t len = npos) const; #include <iostream> #include <string>using namespace std;int main(){ string s1 = "i love lyy, 阅读全文
摘要：
string (1) size_t rfind (const string& str, size_t pos = npos) const noexcept; c-string (2) size_t rfind (const char* s, size_t pos = npos) const; buf 阅读全文
摘要：
string (1) size_t find (const string& str, size_t pos = 0) const noexcept; c-string (2) size_t find (const char* s, size_t pos = 0) const; buffer (3) 阅读全文
摘要：
1. compare string (1) 4int compare (const string& str) const noexcept; substrings (2) int compare (size_t pos, size_t len, const string& str) const; i 阅读全文