std::strstr

 

C++

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Feature test macros (C++20)

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Strings library

Null-terminated strings

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Null-terminated byte strings

Functions
Character manipulation
isalnum isalpha islower isupper isdigit isxdigit isblank (C++11)	iscntrl isgraph isspace isprint ispunct tolower toupper
Conversions to numeric formats
atof atoiatolatoll (C++11) strtolstrtoll (C++11)	strtoulstrtoull (C++11) strtofstrtodstrtold (C++11)(C++11) strtoimaxstrtouimax (C++11)(C++11)
String manipulation
strcpy strncpy strxfrm	strcat strncat
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strlen strcmp strncmp strcoll strchr strrchr	strspn strcspn strpbrk strstr strtok
Memory manipulation
memchr memcmp memset	memcpy memmove
Miscellaneous
strerror

 

Defined in header <cstring>
const char* strstr( const char* haystack, const char* needle );
char* strstr(       char* haystack, const char* needle );

Finds the first occurrence of the byte string needle in the byte string pointed to by haystack. The terminating null characters are not compared.

Parameters

haystack	-	pointer to the null-terminated byte string to examine
needle	-	pointer to the null-terminated byte string to search for

Return value

Pointer to the first character of the found substring in haystack, or a null pointer if no such character is found. If needle points to an empty string, haystack is returned.

Example

Run this code

#include <cstring>
#include <iostream>
 
int main()
{
    const char* str = "Try not. Do, or do not. There is no try.";
    const char* target = "not";
    const char* result = str;
 
    while ((result = std::strstr(result, target)))
    {
        std::cout << "Found '" << target 
                  << "' starting at '" << result << "'\n";
 
        // Increment result, otherwise we'll find target at the same location
        ++result;
    }   
}

Output:

Found 'not' starting at 'not. Do, or do not. There is no try.'
Found 'not' starting at 'not. There is no try.'

See also

find	finds the first occurrence of the given substring (public member function of std::basic_string<CharT,Traits,Allocator>)
wcsstr	finds the first occurrence of a wide string within another wide string (function)
strchr	finds the first occurrence of a character (function)
strrchr	finds the last occurrence of a character (function)