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std::strlen(3)		       C++ Standard Libary		  std::strlen(3)

NAME
     std::strlen - std::strlen

Synopsis
	Defined in header <cstring>
	std::size_t strlen( const char* str );

	Returns  the  length  of  the  given byte string, that is, the number of
     characters in a
	character array whose first element is pointed to by str up to	and  not
     including the
	first  null  character.  The  behavior	is undefined if there is no null
     character in the
	character array pointed to by str.

Parameters
	str - pointer to the null-terminated byte string to be examined

Return value
	The length of the null-terminated string str.

Possible implementation
	std::size_t strlen(const char* start)
	{
	    // NB: start is not checked for nullptr!
	    const char* end = start;
	    while (*end != '\0')
		++end;
	    return end - start;
	}

Example
     // Run this code

      #include <cstring>
      #include <iostream>

      int main()
      {
	  const char str[] = "dog cat\0mouse";

	  std::cout << "without null character: " << std::strlen(str) << '\n'
		    << "with null character: " << sizeof str << '\n';
      }

Output:
      without null character: 7
      with null character: 14

See also
	wcslen returns the length of a wide string
	       (function)
	mblen  returns the number of bytes in the next multibyte character
	       (function)
	C documentation for
	strlen

http://cppreference.com 	   2024.06.10			  std::strlen(3)
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