4.6 (StrCopy)

//https://vk.com/evgenykravchenko0

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char *str_copy(char *dest, const char *src)
{
  char *d = dest;
  while ( *d++ = *src++ )
  {

  }
  return dest;
}

#include <stdio.h>

int main()
{
  char* str = "Hello world.";
  char dst[13];
  str_copy(dst, str);
  dst[0] == 'H';
  dst[11] == '.';

  printf("%s",dst, str);

  return 0;
}