Leibniz to find π

pi.c

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


double calc(unsigned long n) {
    unsigned long i = 0;
    double sum = 0;
    while (i < n) {
        sum += (i%2 == 0 ? 1.0 : -1.0) / (2*i+1);
        i++;
    }

    return sum*4;
}


int main(int c, char **arr) {
    printf("%.20f\n", calc(atol(arr[1])));
}

pi.py

#!/usr/bin/env python3
from sys import argv


def calc(n):
    i = 0
    sum = 0
    while i < n:
        sum += (1 if i%2 == 0 else -1) / (2*i+1)
        i += 1

    return sum*4


if __name__ == '__main__':
    print('%.20f' %calc(int(argv[1])))

pic.py

#!/usr/bin/env python3
from sys import argv
import ctypes


pic = ctypes.cdll.LoadLibrary('./libpi.so')
pic.calc.restype = ctypes.c_double
print('%.20f' %pic.calc(ctypes.c_ulong(int(argv[1]))))