java.lang.Error: Unresolved compilation problem: Syntax error, insert "( )" to complete Expression

求圆的面积和周长

public class Circle {
    Scanner scanner = new Scanner(System.in);
    int r = scanner.nextInt();
    double s,c;
    final double PI=3.1415926;
    public void space()
    {
        s=PI*r*r;
        System.out.println("圆的面积是：" + s);
    }
    public void circumference()
    {
        c=2*PI*r;
        System.out.println("圆的周长是：" + c);
    }
    public static void main(String[] args){
        Circle C = new Circle;
        C.space();
        C.circumference();
    }
}

改为Circle C = new Circle();