positive remainders returning negative?

[pixelpuffin]

int Fib1 = 1;
int Fib2 = 2;
int Fib3 = 0;
int randomynumber;
int Loop;

while (Loop < 100) {
Fib3 = Fib2 + Fib1;
Fib1 = Fib2;
Fib2 = Fib3;
randomynumber = Fib2 % 17;
cout << randomynumber << " ";
if (Loop % 10 == 0) {
cout << "\n"
}
}

this returns negative numbers sometimes
what did i do wrong

side note this is not the complete program it is only the part with the problem because the complete code is sort of longish and very confusing

[ne555]

overflow
there is a limit on the numbers that an int may store http://www.cplusplus.com/reference/climits/

You may use modular arithmetic
(a+b) mod c = (a mod c + b mod c) mod c

[pixelpuffin]

thanks that worked perfectly
i didn't expect them to get so big so fast