RosettaCodeData/Task/Almost-prime/C++/almost-prime.cpp

33 lines
871 B
C++

#include <cstdlib>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <list>
bool k_prime(unsigned n, unsigned k) {
unsigned f = 0;
for (unsigned p = 2; f < k && p * p <= n; p++)
while (0 == n % p) { n /= p; f++; }
return f + (n > 1 ? 1 : 0) == k;
}
std::list<unsigned> primes(unsigned k, unsigned n) {
std::list<unsigned> list;
for (unsigned i = 2;list.size() < n;i++)
if (k_prime(i, k)) list.push_back(i);
return list;
}
int main(const int argc, const char* argv[]) {
using namespace std;
for (unsigned k = 1; k <= 5; k++) {
ostringstream os("");
const list<unsigned> l = primes(k, 10);
for (list<unsigned>::const_iterator i = l.begin(); i != l.end(); i++)
os << setw(4) << *i;
cout << "k = " << k << ':' << os.str() << endl;
}
return EXIT_SUCCESS;
}