Niuke.com Wrong Question Collection 7

1. Constructors cannot be inherited and can only be called explicitly or implicitly

2.

public class Test {
    static int x = 10;

    static {
        x += 5;
    }

    public static void main(String[] args) {
        System.out.println("x=" + x);
    }

    static {
        x /= 3;
    }

    ;
}

Answer: x=5

class A {
    static {
        System.out.println("Parent class static code block");
    }

    public A() {
        System.out.println("Parent class constructor");
    }

    {
        System.out.println("Parent class initialization block");
    }
}

public class B extends A {
    static {
        System.out.println("Subclass static code block");
    }

    public B() {
        System.out.println("Subclass constructor");
    }

    {
        System.out.println("Subclass initialization block");
    }

    public static void main(String[] args) {
        new B();
    }
}

Sequence: parent class static code block --> child class static code block --> parent class ordinary code block --> parent class construction method --> child class code block --> child class construction method;

3.

public class Test {
    public static void main(String[] args) {
        double d1 = -0.5;
        System.out.println("Ceil d1=" + Math.ceil(d1));
        System.out.println("floor d1=" + Math.floor(d1));
    }
}

Answer:

Ceil d1 = -0.0

floor d1=-1.0

Parse:

floor returns the largest integer not greater than  

round is the calculation of 4 rounding to 5. When entering, it is the 
round method to an integer greater than it. It means "rounding up". The algorithm is Math.floor(x+0.5), which is to add 0.5 to the original number and then go down. Rounding, so the result of Math.round(11.5) is 12 and the result of Math.round(-11.5) is -11.
ceil is the smallest integer not less than him 

The symbol does not change, the type does not change