std::basic_string<CharT,Traits,Allocator>::copy

< cpp‎ | string‎ | basic string

size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;		(until C++20)
constexpr size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const;		(since C++20)

Copies a substring [pos, pos+count) to character string pointed to by dest. If the requested substring lasts past the end of the string, or if count == npos, the copied substring is [pos, size()). The resulting character string is not null-terminated.

If pos > size(), std::out_of_range is thrown.

Parameters

dest	-	pointer to the destination character string
count	-	length of the substring
pos	-	position of the first character to include

Return value

number of characters copied

Exceptions

std::out_of_range if pos > size().

Complexity

linear in count

Example

#include <string>
#include <iostream>
 
int main()
{
  std::string foo("quuuux");
  char bar[7]{};
  foo.copy(bar, sizeof bar);
  std::cout << bar << '\n';
}

Output:

quuuux