Hello guys!

I have to make a program in c++ that displays on the screen all the friends numbers <= n . For example , if n is 11 then it should display the pairs :

(3,5);(5,7)

Friends numbers are those numbers whose difference is 2 and both numbers are prime. The difference between 5 and 7 is 2 and they are prime.The same is for 5 and 7,11 and 13 and so on.

Here is my piece of code and it doesn't work....

Could someone help me out with the program ?Code:#include <iostream> using namespace std; int main(){ int n,d1,a,b,ok1,ok2,d2,i; cin >> n; for (a = 3;a < n;a++) {ok1 = 0; for (d1 = 2;d1 <= a/2;d1++) if (a % d1 == 0) ok1 = 1;} if (ok1 == 0) { for (a = 3;a < n;a++) b = a+2; ok2 = 0; for (d2 = 2;d2 <= b/2;d2++) { if (b % d1 == 0) ok2 = 1;} if (ok2 == 0) cout << "(" << a << "," << b << ")" << ";"; a++; } } return 0; }

Thanks in advance !