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is_prime1.cpp
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is_prime1.cpp
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#include <iostream>
using namespace std;
template <int n, int k>
struct is_prime_helper {
const static bool value = (n % k != 0) && is_prime_helper<n, k-1>::value;
};
template <int n>
struct is_prime_helper<n, 1> {
const static bool value = true;
};
template <int n>
struct is_prime {
const static bool value = is_prime_helper<n, n-1>::value;
};
/*
is_prime_helper x k =
if x mod k == 0:
false
else:
if x == 1:
true
else:
is_prime_helper x (k-1)
is_prime x = is_prime_helper x (x-1)
*/
#include <cassert>
template <int p>
struct ModuloInt {
int value;
ModuloInt(int v): value(v) {}
ModuloInt<p> operator+ (ModuloInt<p> o) {
return ModuloInt((o.value + value) % p);
}
template <typename A = typename std::enable_if<is_prime<p>::value >::type >
ModuloInt<p> invert() {
//static_assert is_prime<p>::value, "attempting to invert a number modulo non-prime";
return 0 /*dummy*/;
}
};
int main() {
cout << is_prime<13>::value << endl;
ModuloInt<12> a = 5;
a.invert();
}