Int parsing and simple operation

int_parse.cxx

// Compile with: g++ --std=c++11 -O3

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>

int main() {
	std::ios_base::sync_with_stdio(false);

	std::vector<long int> v (
		std::istream_iterator<long int>(std::cin),
		std::istream_iterator<long int>()
	);

	std::cout << v.size() << std::endl;
}

IntParse.hs

{-# LANGUAGE BangPatterns #-}
{-# OPTIONS_GHC -Odph #-}

import qualified Data.ByteString.Char8      as S
import qualified Data.Vector                as U

-- Read ints from stdin into a vector then print the length.
main = S.getContents >>= print . U.length . parse

-- Fill a new vector from a file containing a list of numbers.
parse = U.unfoldr step
  where
     step !s = case S.readInt s of
        Nothing       -> Nothing
        Just (!k, !t) -> Just (k, S.tail t)

RandomInts.hs

module Main where

import Control.Monad
import Data.Functor
import System.Random

main = do
  n <- readLn :: IO Int
  rs <- randomRs (1, maxBound) <$> newStdGen :: IO [Int]
  forM_ (take n rs) print