Perlの練習

operator.pl

system('chcp 65001');
system('cls');

sub neg {
  return -$_[0];
}

sub add {
  return($_[0] + $_[1]);
}

sub subs {
  return(&add($_[0], neg($_[1])));
}

sub mult {
  local($r) = $_[2];
  
  if ($_[1] == 0) {
    return $r;
  }
  
  $r = &add($r, $_[0]);
  return &mult($_[0], &subs($_[1], 1), $r);
}

sub div {
  local($a) = $_[0];
  local($c) = $_[2];
  
  if (&subs($a, $_[1]) < 0) {
    return $c;
  }
  
  $a = &subs($a, $_[1]);
  $c = &add($c, 1);
  
  return &div($a, $_[1], $c);
}

sub mod {
  local($a) = $_[0];
  if (&subs($a, $_[1]) < 0) {
    return $a;
  }
  
  $a = &subs($a, $_[1]);
  
  return &mod($a, $_[1]);
}

sub pow {
  local($r) = $_[2];
  if ($r == 0) {
    $r = 1;
  }
  
  if ($_[1] == 0) {
   return $r;
  }
  
  $r = &mult($r, $_[0]);
  
  return &pow($_[0], &subs($_[1], 1), $r);
}

print('9足す1: ' . &add(9, 1) . "\n");
print('7引く4: ' . &subs(7, 4) . "\n");
print('3の12倍: ' . &mult(3, 12) . "\n");
print('15割る5: ' . &div(15, 5) . "\n");
print('11割る6の余り: ' . &mod(11, 6) . "\n");
print('2の10乗: ' . &pow(2, 10) . "\n");

system('pause');