RosettaCodeData/Task/Deceptive-numbers/C++/deceptive-numbers-1.cpp

34 lines
784 B
C++

#include <gmpxx.h>
#include <iomanip>
#include <iostream>
bool is_prime(int n) {
if (n < 2)
return false;
if (n % 2 == 0)
return n == 2;
if (n % 3 == 0)
return n == 3;
for (int p = 5; p * p <= n; p += 4) {
if (n % p == 0)
return false;
p += 2;
if (n % p == 0)
return false;
}
return true;
}
int main() {
std::cout << "First 100 deceptive numbers:\n";
mpz_class repunit = 11;
for (int n = 3, count = 0; count != 100; n += 2) {
if (n % 3 != 0 && n % 5 != 0 && !is_prime(n) &&
mpz_divisible_ui_p(repunit.get_mpz_t(), n))
std::cout << std::setw(6) << n << (++count % 10 == 0 ? '\n' : ' ');
repunit *= 100;
repunit += 11;
}
}