#include "stdio.h"   #include "stdlib.h"        #define SCALE 10000   #define ARRINIT 2000        void pi_digits(int digits) {       int carry = 0;       int arr[digits + 1];       for (int i = 0; i <= digits; ++i)           arr[i] = ARRINIT;       for (int i = digits; i > 0; i-= 14) {           int sum = 0;           for (int j = i; j > 0; --j) {               sum = sum * j + SCALE * arr[j];               arr[j] = sum % (j * 2 - 1);               sum /= j * 2 - 1;           }           printf("%04d", carry + sum / SCALE);           carry = sum % SCALE;       }   }        int main(int argc, char** argv) {       int n = argc == 2 ? atoi(argv[1]) : 100;       pi_digits(n);            return 0;   }