The program pops up but then i get an error saying y2 is being used without being initialized. But i can't find it. If you find any other errors please tell me.

Code:#include <iostream> #include <cmath> #include <iomanip> using namespace std; double distance(double x1, double y1, double x2, double y2); double radius(double x1, double y1, double x2, double y2); double diameter(double rad); double circumference(double rad); double area(double rad); const double Pi = 3.1416; int main() { double origin1, origin2, pt1, pt2, x1, x2, y1, y2, rad; rad = (x1,y1,x2,y2); cout << setprecision(2) << fixed << showpoint; cout << "Please input the origin of your circle" << endl; cin >> origin1 >> origin2; cout << "Please input a point on the circle" << endl; cin >> pt1 >> pt2; cout << "Your origin is: " << "(" << origin1 << "," << origin2 << ")" << endl; cout << "Your point is: " << "(" << pt1 << "," << pt2 << ")" << endl; cout << "The distance between the point and the origin is" << distance(pt1, origin1, pt2, origin2) << endl; cout << "The radius of your circle is: " << radius(pt1, origin1, pt2, origin2) << endl; cout << "The diameter of your circle is: " << diameter(rad) << endl; cout << "The circumference of your circle is: " << circumference(rad) << endl; cout << "The area of your circle is: " << area(rad) << endl; return 0; } double distance(double x1, double y1, double x2, double y2) { return sqrt(pow(x1-y1,2) + pow(x2-y2,2)); } double radius(double x1, double y1, double x2, double y2) { return distance(x1, y1, x2, y2); } double diameter(double rad) { return 2 * rad; } double circumference(double rad) { return Pi * rad; } double area(double rad) { return pow(rad, 2); }