1.素数对猜想

#include<cmath>
#include<iostream>
using namespace std;
bool isPrime(int n)
{
if (n == 1 || n == 0)
return false;
if (n == 2)
return true;
int tmp = (int)sqrt((double)n);
for (int i = 2; i <= tmp; i++)
{
if (n%i == 0)
return false;
}

return true;
}
int main()
{
int num, count = 0;
cin >> num;
for (int i = 3; i <= num - 2; i++)
{
if (isPrime(i) && isPrime(i + 2))
count++;
}
cout << count << endl;

return 0;
}