#include <iostream>
#include <vector>
#include <cmath>
#include <iomanip>

using namespace std;

int main(void)
{   cout << "Input the largest positive integer to check: ";
    int maxN;
    cin >> maxN;
    vector <int> primes;
    int n;
    n = (int)sqrt(maxN);
    for (int i = maxN; i > n; i = i - 1)
    {   bool isPrime = true;
        for (int j = 2; j <= n; j = j + 1)
        {   if (i%j == 0)
            {   isPrime = false;
            }
        }
            if (isPrime)
            {   //cout << i << " ";
                primes.push_back(i);
            }
    }
    cout << "\n\nThere are " << primes.size() << " prime numbers <= " << maxN << "\n";
    return 0;
}

#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main(void)
{   int y, x;
    for(y = -10; y <= 10; y = y + 1)
    {   for(x = -10; x <= 10; x = x + 1)
        {   float res;
	    int ires;
	    ires = (int)sqrt(x*x + y*y);
	    if(ires == 10)
	    {   cout << "*";
	    }
	    if(ires == 7 && y > 0)
	    {   cout << "=";
	    }
	    res = (sqrt((x^2) + (y^2)));
	    if(res < 1.25)
	    {   cout << "*";
	    }
	    res = (sqrt(((x + 4)^2) + ((y + 4)^2)));
	    if(res < 2)
	    {   cout << "\\";
	    }
	    res = (sqrt(((x - 4)^2) + ((y + 4)^2)));
	    if(res < 2)
	    {   cout << "/";
	    }
            cout << "   ";
	}
        cout << endl;
    }
return 0;
}