1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // REQUIRES: long_tests 11 12 // Not a portable test 13 14 // <__hash_table> 15 16 // size_t __next_prime(size_t n); 17 18 // If n == 0, return 0, else return the lowest prime greater than or equal to n 19 20 #include <__hash_table> 21 #include <cassert> 22 23 bool 24 is_prime(size_t n) 25 { 26 switch (n) 27 { 28 case 0: 29 case 1: 30 return false; 31 } 32 for (size_t i = 2; i*i <= n; ++i) 33 { 34 if (n % i == 0) 35 return false; 36 } 37 return true; 38 } 39 40 int main() 41 { 42 assert(std::__next_prime(0) == 0); 43 for (std::size_t n = 1; n <= 100000; ++n) 44 { 45 std::size_t p = std::__next_prime(n); 46 assert(p >= n); 47 for (std::size_t i = n; i < p; ++i) 48 assert(!is_prime(i)); 49 assert(is_prime(p)); 50 } 51 } 52
