从Java派生类调用基类构造函数
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时间：2020-08-14 01:23:13 来源:igfitidea点击:
Calling a base class constructor from derived class in Java
提问by akshay
I have a class as follows:
我有一个类如下：
public class Polygon extends Shape{
private int noSides;
private int lenghts[];
public Polygon(int id,Point center,int noSides,int lengths[]) {
super(id, center);
this.noSides = noSides;
this.lenghts = lengths;
}
}
Now a regular polygon is a polygon whose all sides are equal. What should be the constructor of my regular polygon?
现在正多边形是所有边都相等的多边形。我的正多边形的构造函数应该是什么？
public Regularpolygon extends Polygon{
//constructor ???
}
采纳答案by missingfaktor
public class Polygon extends Shape {
private int noSides;
private int lenghts[];
public Polygon(int id,Point center,int noSides,int lengths[]) {
super(id, center);
this.noSides = noSides;
this.lenghts = lengths;
}
}
public class RegularPolygon extends Polygon {
private static int[] getFilledArray(int noSides, int length) {
int[] a = new int[noSides];
java.util.Arrays.fill(a, length);
return a;
}
public RegularPolygon(int id, Point center, int noSides, int length) {
super(id, center, noSides, getFilledArray(noSides, length));
}
}
回答by JWhiz
Your constructor should be
你的构造函数应该是
public Regularpolygon extends Polygon{
public Regularpolygon (int id,Point center,int noSides,int lengths[]){
super(id, center,noSides,lengths[]);
// YOUR CODE HERE
}
}
回答by user2290013
class Foo {
Foo(String str) { }
}
class Bar extends Foo {
Bar(String str) {
// Here I am explicitly calling the superclass
// constructor - since constructors are not inherited
// you must chain them like this.
super(str);
}
}
