std::basic_string::find

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size_type find( const basic_string& str, size_type pos = 0 ) const;	(1)

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

size_type find( const CharT* s, size_type pos = 0 ) const;	(3)

size_type find( CharT ch, size_type pos = 0 ) const;	(4)

Finds the first substring equal to the given character sequence. Search begins at pos, i.e. the found substring must not begin in a position preceding pos.

1) Finds the first substring equal to str.

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

3) Finds the first 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 first character ch.

#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 from beginning of string
    n = s.find("is");
    print(n, s);
 
    // search from position 5
    n = s.find("is", 5);
    print(n, s);
 
    // find a single character
    n = s.find('a');
    print(n, s);
 
    // find a single character
    n = s.find('q');
    print(n, s);
}

Output:

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

[edit] See also


strstr	finds the first occurrence of a substring of characters (function)

wcsstr	finds the first occurrence of a wide string within another wide string (function)

strchr	finds the first occurrence of a character (function)

wcschr	finds the first occurrence of a wide character in a wide string (function)

rfind	find the last occurrence of a substring (public member function)

find_first_of	find first occurrence of characters (public member function)

find_first_not_of	find first absence of characters (public member function)

find_last_of	find last occurrence of characters (public member function)

find_last_not_of	find last absence of characters (public member function)

search	searches for a range of elements (function template)

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)

str	-	string to search for
pos	-	position at which to start the search
count	-	length of substring to search for
s	-	pointer to a character string to seach for
ch	-	character to search for

std::basic_string::find

Contents

[edit] Parameters

[edit] Return value

[edit] Example

[edit] See also