C vs Fortran benchmark

README.md

On my machine, the timings are:

Fortran:

$ time ./a_f
   249999999500000000

real	0m1.142s
user	0m1.138s
sys	0m0.002s

C:

$ time ./a_c
249999999500000000

real	0m0.778s
user	0m0.776s
sys	0m0.001s

C++:

time ./a_c++ 
249999999500000000

real	0m0.751s
user	0m0.750s
sys	0m0.001s

So C++ is 1.142 / 0.751 = 1.521 times faster than Fortran.

a.c

// Compile with:
// gcc -O3 -march=native -ffast-math -funroll-loops a.c
#include "stdio.h"

int main()
{
    int i = 0;
    long int s = 0;
    while (i < 1000000000) {
        if (i % 2 == 0) s += i;
        i++;
    }
    printf("%ld\n", s);
}

a.cc

// Compile with:
// g++ -O3 -march=native -ffast-math -funroll-loops a.cc
#include <iostream>

int main()
{
    int i = 0;
    long int s = 0;
    for (int i = 0; i < 1000000000; ++i)
      if (i % 2 == 0) s += i;
    std::cout << s << std::endl;
}

a.f90

program test
! Compile with:
! gfortran -O3 -march=native -ffast-math -funroll-loops a.f90
implicit none
integer, parameter :: dp=kind(0.d0)
integer :: i
integer(8) :: s
s = 0
do i = 0, 1000000000-1
    if (mod(i, 2) == 0) s = s + i
end do
print *, s
end program

Makefile

all : a_f a_c a_c++

a_f : a.f90
	gfortran -O3 -march=native -ffast-math -funroll-loops a.f90 -o a_f

a_c : a.c
	gcc -O3 -march=native -ffast-math -funroll-loops a.c -o a_c

a_c++ : a.cc
	g++ -O3 -march=native -ffast-math -funroll-loops a.cc -o a_c++

clean :
	rm -rf a_f a_c a_c++

.PHONY : all clean