HelloWorld.nane和HelloWorld.this.name区别在于,
第一个语句是非法的,想要这样表述,必须对类进行实例化然后再访问它的成员变量:HelloWorld hello=new HelloWorld();hello.name
而第二个语句恰恰就是实现这样的功能,这样就能体现this的作用了。
第一个语句是非法的,想要这样表述,必须对类进行实例化然后再访问它的成员变量:HelloWorld hello=new HelloWorld();hello.name
而第二个语句恰恰就是实现这样的功能,这样就能体现this的作用了。
2016-05-24
static String className = "JAVA开发一班"; System.out.println( "班级:"+HelloWorld.className );
2016-05-22
package project_abstract;
public class Circle extends Shape {
public double r;
public Circle(double r) {
this.r = r;
}
public double perimeter() {
// TODO Auto-generated method stub
return (2*3.14*r);
}
public double area() {
return (3.14*r*r);
}
//cal就是输出显示计算结果,字数限制发不了见谅
}
public class Circle extends Shape {
public double r;
public Circle(double r) {
this.r = r;
}
public double perimeter() {
// TODO Auto-generated method stub
return (2*3.14*r);
}
public double area() {
return (3.14*r*r);
}
//cal就是输出显示计算结果,字数限制发不了见谅
}
2016-05-21
package project_abstract;
public abstract class Shape {
public abstract double perimeter();
public abstract double area();
public abstract void cal();
}
public abstract class Shape {
public abstract double perimeter();
public abstract double area();
public abstract void cal();
}
2016-05-21
package project_abstract;
public class Initial {
public static void main(String[] args) {
// TODO Auto-generated method stub
Shape rec = new Rectangle(4, 3);
Shape cir = new Circle(2);
rec.cal();
cir.cal();
}
}
public class Initial {
public static void main(String[] args) {
// TODO Auto-generated method stub
Shape rec = new Rectangle(4, 3);
Shape cir = new Circle(2);
rec.cal();
cir.cal();
}
}
2016-05-21