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///
/// @file prev_prime1.cpp
/// @brief Test prev_prime() of primesieve::iterator.
///
/// Copyright (C) 2017 Kim Walisch, <kim.walisch@gmail.com>
///
/// This file is distributed under the BSD License. See the COPYING
/// file in the top level directory.
///
#include <primesieve.hpp>
#include <stdint.h>
#include <cstdlib>
#include <exception>
#include <iostream>
#include <vector>
using namespace std;
void check(bool OK)
{
cout << " " << (OK ? "OK" : "ERROR") << "\n";
if (!OK)
exit(1);
}
int main()
{
vector<uint64_t> primes;
primesieve::generate_primes(100000, &primes);
primesieve::iterator it;
uint64_t back = primes.size() - 1;
uint64_t prime;
for (uint64_t i = back; i > 0; i--)
{
it.skipto(primes[i] + 1);
prime = it.prev_prime();
cout << "prev_prime(" << primes[i] + 1 << ") = " << prime;
check(prime == primes[i]);
it.skipto(primes[i]);
prime = it.prev_prime();
cout << "prev_prime(" << primes[i] << ") = " << prime;
check(prime == primes[i - 1]);
}
it.skipto(100000000);
prime = it.prev_prime();
uint64_t sum = 0;
// iterate over the primes below 10^8
for (; prime > 0; prime = it.prev_prime())
sum += prime;
cout << "Sum of the primes below 10^8 = " << sum;
check(sum == 279209790387276ull);
for (uint64_t i = 0; i < 1000; i++)
{
prime = it.prev_prime();
cout << "prev_prime(0) = " << prime;
check(prime == 0);
}
for (uint64_t i = 0; i < 1000; i++)
{
uint64_t old = prime;
prime = it.next_prime();
cout << "next_prime(" << old << ") = " << prime;
check(prime == primes[i]);
}
it.skipto(primes.back());
for (uint64_t i = 0; i < 1000; i++)
{
prime = it.prev_prime();
uint64_t p1 = primes.size() - (i + 1);
uint64_t p2 = primes.size() - (i + 2);
cout << "prev_prime(" << primes[p1] << ") = " << prime;
check(prime == primes[p2]);
}
for (uint64_t i = 0; i < 1000; i++)
{
uint64_t old = prime;
uint64_t j = primes.size() - 1000 + i;
prime = it.next_prime();
cout << "next_prime(" << old << ") = " << prime;
check(prime == primes[j]);
}
it.skipto(18446744073709551615ull, 18446744073709551557ull);
prime = it.prev_prime();
cout << "prev_prime(" << 18446744073709551615ull << ") = " << prime;
check(prime == 18446744073709551557ull);
cout << endl;
cout << "All tests passed successfully!" << endl;
return 0;
}
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