learning functions and I am having trouble with some local variables. I keep getting "warning C4700: uninitialized local variable 'y' used", same for the variable x. Are my loops in combinations with cin >> messing up the code? I am pretty new to programming, any help would be greatly appreciated. Heres the code:

Code:#include <iostream> using namespace std; //function prototype double calculateRetail(double, double); int main() { double x, y, z; while(x < 0) { cout << "This progam calculates and displays an items retail price. Enter the whole sale price...\n"; cin >> x; } while(y < 0) { cout << "Enter the markup percentage...\n"; cin >> y; } z = calculateRetail(x, y); cout << z << " is the retail price.\n"; return 0; } double calculateRetail(double x, double y) { return x * y * .01; }