# include <stdio.h>

void copy_string ( char *to, char *from );

int main ( )
{
  char s1[] = "Charles";
  char s2[80] = "William";
  char *s3 = "Frank";

  printf ( "  S1 = \"%s\".\n", s1 );
  printf ( "  S2 = \"%s\".\n", s2 );
  printf ( "  S3 = \"%s\".\n", s3 );

  copy_string ( s2, s1 );

  printf ( "\n" );
  printf ( "After call to copy_string(s2,s1):\n" );
  printf ( "\n" );

  printf ( "  S1 = \"%s\".\n", s1 );
  printf ( "  S2 = \"%s\".\n", s2 );
  printf ( "  S3 = \"%s\".\n", s3 );

  copy_string ( s2, s3 );

  printf ( "\n" );
  printf ( "After call to copy_string(s2,s3):\n" );
  printf ( "\n" );

  printf ( "  S1 = \"%s\".\n", s1 );
  printf ( "  S2 = \"%s\".\n", s2 );
  printf ( "  S3 = \"%s\".\n", s3 );

  return 0;
}
void copy_string ( char *to, char *from )
{
  for ( ; *from != '\0'; from++, to++ )
  {
    *to = *from;
  }
  *to = '\0';
}