No enclosing instance is accessible. Must qualify the allocation with an enclosing instance of type (e.g. x.new A() where x is an instance of )

Nick Ninov :

I'm new to programming and I'll be studying it next year in uni. In my public static void main ... I can't create a new SimpleCircle. This error occurs only on my circle. Thank you very much for the help! :)

public class TestSimpleCircle {

    class SimpleCircle {
        double radius;

        SimpleCircle(){
            radius = 1;
        }

        SimpleCircle(double newRadius){
            radius = newRadius;
        }

        double getArea() {
            return radius * radius * Math.PI;
        }

        double getPerimeter() {
            return 2 * radius * Math.PI;
        }

        void setRadius(double newRadius) {
            radius = newRadius;
        }
    }

    public static void main(String [] args) {
        SimpleCircle circle = new SimpleCircle();
        System.out.println("the area of the circle of radius "+circle.radius+" is "+circle.getArea());

        SimpleCircle circle2 = new SimpleCircle(25);
        System.out.println("the area of the circle of radius "+circle2.radius+" is "+circle2.getArea());

        SimpleCircle circle3 = new SimpleCircle(125);
        System.out.println("the area of the circle of radius "+circle3.radius+" is "+circle3.getArea());

        circle.radius = 100;
        System.out.println("The area of the circle of radius "+circle.radius+" is "+circle.getArea());
    }
}

Ivan :

You declared you SimpleCircle class as inner class for TestSimpleCircle. You need either move it into a separate file or declare it as