pi.c

#define N 1000

#include "stdio.h"
#include "stdlib.h"
#define PERC N + 1
int main(){
  FILE* file = fopen( "pi.txt", "w" );
  if (file == NULL)
  {
      printf("Error opening file!\n");
      exit(1);
  }
  char* pi = (char*)malloc( sizeof(char) * ( PERC  )  );
  int last = 0;
  int boxes = ( PERC ) * 10 / 3 ;
  int* reminders = (int*)malloc(sizeof(int) * boxes );
  for( int i = 0; i < boxes; i++ )
    reminders[i] = 2;
  int heldDigits = 0;
  for( int i = 0; i < PERC; i++ ){
    int carriedOver = 0;
    int sum = 0;
    for ( int j = boxes - 1; j >= 0; j-- ){
      reminders[ j ] *= 10;
      sum = reminders[j] + carriedOver;
      int quotient = sum / ( j * 2 + 1 );
      reminders[ j ] = sum % ( j * 2 + 1 );
      carriedOver = quotient * j;
    }
    reminders[0] =  sum % 10;
    int q = sum / 10;
    if ( q == 9 ) {
      heldDigits++;
    }else if ( q == 10 ){
      q = 0;
      for( int k = 1; k < heldDigits; k++ ){
        char replaced = pi[ i - k ];
        if( replaced == '9' ){
          replaced = '0';
        } else {
          replaced++;
        }
        pi[i-k] = replaced;
      }

      heldDigits = 1;
    } else {
      heldDigits = 1;
    }
    pi[last++] = q + '0';
  }
  for( int i = 0; i < PERC; i++ ){
    if( i == 1 )
      fprintf(file,".");
    fprintf( file, "%c", pi[i] );
  }
  fprintf(file,"\n");
  return 0;
}