std::basic_string::rfind - cppreference.com

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`size_type rfind( const basic_string& str, size_type pos = npos ) const;`	(1)

`size_type rfind( const CharT* s, size_type pos, size_type count ) const;`	(2)

`size_type rfind( const CharT* s, size_type pos = npos ) const;`	(3)

`size_type rfind( CharT ch, size_type pos = npos ) const;`	(4)

Finds the last substring equal to the given character sequence. Search begins at pos, i.e. only the substring [0, pos) is considered in the search. If npos is passed as pos whole string will be searched.

1) Finds the last substring equal to str.

2) Finds the last substring equal to the first count characters of the character string pointed to by s. s can include null characters.

3) Finds the last substring equal to the character string pointed to by s. The length of the string is determined by the first null character.

4) Finds the last character ch.

Parametri

str	-	stringa da ricercare Original: string to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
count	-	lunghezza della stringa da cercare Original: length of substring to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
s	-	puntatore a una stringa di caratteri per cercare i per Original: pointer to a character string to seach for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ch	-	carattere da cercare Original: character to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Valore di ritorno

posizione del primo carattere della sottostringa trovato o npos in mancanza di tale stringa viene trovata.

Original:

position of the first character of the found substring or npos if no such substring is found.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Esempio

#include <string>
#include <iostream>

void print(std::string::size_type n, std::string const &s)
{
  if(n == std::string::npos)
    std::cout << "not found\n";
  else
    std::cout << "found: " << s.substr(n) << '\n';
}

int main()
{
  std::string::size_type n;
  std::string const s = "This is a string";

  // search backwards from beginning of string
  n = s.rfind("is");
  print(n, s);
  // search backwards from position 4
  n = s.rfind("is", 4);
  print(n, s);
  // find a single character
  n = s.rfind('s');
  print(n, s);
  // find a single character
  n = s.rfind('q');
  print(n, s);
}

Output:

found: is a string
found: is is a string
found: string
not found

Vedi anche


find	trova la prima occorrenza di una sottostringa (metodo pubblico) [modifica]

find_first_of	trovare prima occorrenza di caratteri Original: find first occurrence of characters The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) [modifica]

find_first_not_of	trovare prima assenza di caratteri Original: find first absence of characters The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) [modifica]

find_last_of	trovare ultima occorrenza di caratteri Original: find last occurrence of characters The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) [modifica]

find_last_not_of	trovare assenza ultima di caratteri Original: find last absence of characters The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) [modifica]