#include<iostream>
#include<cstdlib>

using namespace std;

bool first(int n)
{
	if (n < 2)
		return false;			
	for (int i = 2; i * i <= n; i++)
		if (n % i == 0)
			return false;		
	return true;
}
int main()
{
	int up, down,sum;
sum=0;
	cout << "Podaj liczbę gorna: ";
	cin >> up;
	cout << "Podaj liczbę dolna: ";
	cin >> down;
	for (; down <= up; down++)
	{
        if (first(down)==true) {
        	sum+=down;
        	cout<<"liczba "<<down<<"jest pierwsza\n";
        	}  
	}
	cout<<sum;
    cout<<endl;
	system("pause");
	return 0;
}



==========================================================================================



#include <iostream>
#include <cstdlib>
#include <windows.h>

using namespace std;

	void gotoxy ( int x, int y)
	{
		COORD coord;
		coord.X = x;
		coord.Y = y;
		SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);
	}
int main(int argc, char** argv)
{
    for (int i=1;i<=9;i++)
   {
       gotoxy(2,i);
       cout<<"|";
       }
   for (int i=1;i<=23;i++)
   {
       gotoxy(i,2);
       cout<<"-";
       }
   for (int i=3;i<=23;i++)
   {
       gotoxy(3,1);
       cout<<"  1  2  3  4  5  6  7";
       }
   for (int i=1;i<=9;i++)
   {
       gotoxy(1,3);
       cout<<"1\n 2\n 3\n 4\n 5\n 6\n 7\n";
       }
    for (int i=3;i<=23;i++)
   {
       gotoxy(3,3);
       cout<<"  1  2  3  4  5  6  7";
       }
   for (int i=3;i<=23;i++)
   {
       gotoxy(3,4);
       cout<<"  2  4  6  8 10 12 14";
       }
       for (int i=3;i<=23;i++)
   {
       gotoxy(3,5);
       cout<<"  3  6  9 12 15 18 21";
       }
       for (int i=3;i<=23;i++)
   {
       gotoxy(3,6);
       cout<<"  4  8 12 16 20 24 28";
       }
       for (int i=3;i<=23;i++)
   {
       gotoxy(3,7);
       cout<<"  5 10 15 20 25 30 35";
       }
       for (int i=3;i<=23;i++)
   {
       gotoxy(3,8);
       cout<<"  6 12 18 24 30 36 42";
       }
   for (int i=3;i<=23;i++)
   {
       gotoxy(3,9);
       cout<<"  7 14 21 28 35 42 49";
       }
       cout<<endl;
	    system("PAUSE"); 
    return EXIT_SUCCESS; 
}