cin / scanf comparison

README

Comparison between cin and scanf

Usage:

make

./rand > rand.txt
Ctrl-C after a few seconds

wc rand.txt

time ./xor-c < rand.txt
time ./xor-cpp < rand.txt

Makefile

all: xor-c xor-cpp xor-cpp-noflush rand 

test: xor-c xor-cpp xor-cpp-noflush
	time ./xor-c < rand.txt
	time ./xor-cpp < rand.txt
	time ./xor-cpp-noflush < rand.txt

rand: rand.c
	gcc -Wall rand.c -o rand

xor-c: xor.c
	gcc -Wall -O4 xor.c -o xor-c

xor-cpp: xor.cc
	g++ -Wall -O4 xor.cc -o xor-cpp

xor-cpp-noflush: xor-noflush.cc
	g++ -Wall -O4 xor-noflush.cc -o xor-cpp-noflush

rand.c

#include <stdio.h>
#include <time.h>
#include <stdlib.h>

int main(int argc, char **argv) {
  
  srand(time(NULL));
  while (1)
    printf("%d\n", rand());
  
}

xor-noflush.cc

#include <iostream>

int main(int argc, char **argv) {
  
  int parity = 0;
  int x;

  std::ios::sync_with_stdio(false);
  
  while (std::cin >> x)
    parity ^= x;
  std::cout << parity << std::endl;

  return 0;
}

xor.c

#include <stdio.h>

int main(int argc, char **argv) {
  
  int parity = 0;
  int x;

  while (1 == scanf("%d", &x))
    parity ^= x;
  printf("%d\n", parity);

  return 0;
}

xor.cc

#include <iostream>

int main(int argc, char **argv) {
  
  int parity = 0;
  int x;

  while (std::cin >> x)
    parity ^= x;
  std::cout << parity << std::endl;

  return 0;
}