pdp competition phase #1

#include <stdio.h>

int is_prime(int);
int main(void)
{
  FILE* pfin = fopen("function.in","r");
  FILE* pfout = fopen("function.out","w");
  int N = 0,M = 0,K = 0,counter = 0;
  fscanf(pfin,"%d %d",&N,&M);
  fclose(pfin);
  for(K=(N>M?M:N)+1; K<(N>M?N:M); K++){
    if(is_prime(K) && K%2) {
      if(!counter)  fprintf(pfout,"%d",K);
      else fprintf(pfout," %d",K);
      counter++;
    }
  }
  if(counter)
    fprintf(pfout,"\n");
  fclose(pfout);
  return 0;
}
int is_prime(int inum)
{
  for(int icounter=2; icounter<inum/2; icounter++){
    if(!(inum%icounter))
    return 0;
    }
  return 1;
}