きったんの頭_ん中☆

/*
 * pe3.c
 * https://mind.kittttttan.info/c/pe3
 */

/* https://mind.kittttttan.info/c/divs */
#include "divs.h"

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <math.h>
#include <stddef.h>

#ifdef _WIN32
#define UINT64 "I64u"
#else
#define UINT64 "llu"
#endif

void pe3(uint64_t n) {
  static const size_t MAX_DIVS_CNT = 128;
  unsigned long p[MAX_DIVS_CNT];
  size_t len;

  len = get_divs(p, n);
  if (len) {
    printf("Max prime factor of %" UINT64 " is %lu\n", n, p[len - 1]);
  } else {
    printf("%" UINT64 " has no prime factors\n", n);
  }
}

int main() {
  uint64_t n;

  puts("Problem 3:");
  while (1) {
    if (scanf("%" UINT64, &n) != 1) {
      scanf("%*s");
      puts("Input Number.");
    } else {
      if (!n) {
        break;
      }
      pe3(n);
    }
  }

  return 0;
}