Use of the Find () function and the RFind () function in C + +

This article is reproduced from http://blog.csdn.net/youxin2012/article/details/9162415

Application of Find () in string (RFind ()similar, just looking from reverse)The prototypes are as follows: (1) size_t find (const string& str, size_t pos = 0) const; Find Object--string Class object (2) size_t find (const char* s, size_t pos = 0) const;  Find Object--string (3) size_t find (const char* s, size_t pos, size_t N) const;  Find Object--the first n characters of a string (4) size_t find (char c, size_t pos = 0) const; Find Object--character result: Found--Returns the index of the first character not found--returns the String::npos example:

1#include <iostream>//Std::cout2#include <string>//std::string3   4 intMain ()5 {  6STD::stringSTR ("There is needles in this haystack with needles."); 7STD::stringSTR2 ("Needle"); 8   9   //different member versions of Find in the same order as above:Tenstd::size_t found =Str.find (STR2);  One   if(FOUND!=STD::string:: NPOs) AStd::cout <<"First ' needle ' found at:"<< found <<'\ n';  -    -Found=str.find ("Needles is small", found+1,6);  the   if(FOUND!=STD::string:: NPOs) -Std::cout <<"second ' needle ' found at:"<< found <<'\ n';  -    -Found=str.find ("Haystack");  +   if(FOUND!=STD::string:: NPOs) -Std::cout <<"' haystack ' also found at:"<< found <<'\ n';  +    AFound=str.find ('.');  at   if(FOUND!=STD::string:: NPOs) -Std::cout <<"Period found at:"<< found <<'\ n';  -    -   //Let ' s replace the first needle: -Str.replace (Str.find (STR2), Str2.length (),"preposition");//Replace usage -Std::cout << str <<'\ n';  in    -   return 0;  to}

Result: First ' needle ' found at:14second ' needle ' found at:44 ' haystack ' also found At:30period found At:51there is both pre Positions in this haystack with needles other also find_first_of (), find_last_of (), find_first_not_of (), find_last_not_of () function is In the Find string Find criteria that any character satisfiesString Snake1 ("Cobra"); int where = Snake1.find_first_of ("Hark"); returns 3 because the first occurrence of a character in "Hark" in Snake1--cobra is the character ' R ' (3 is C Obra the index of ' r ' in the same vein: int where = snake1.find_last_of ("Hark"); returns 4 because the last occurrence of one character in "Hark" in Snake1--cobra is the character ' a ' (3 for Cobra) Index of R ') 其他同理

Use of the Find () function and the RFind () function in C + +