java - 从方法获取值 (java)

Question

到目前为止，我已经得到了这段代码，但我正在尝试学习如何完成此方法，以便它能够编译所用面的总数并在最后一个打印行中打印该值。问题方法是 getTotalSides，我目前将其设置为返回 0，但我希望它返回总边数，意思是: mp1.getSides() + mp2.getSides() + mp3.getSides() + mp4.getSides( )。

public class TestParts {

public static void main(String[] args) {

    MyPolygon mp1 = new MyPolygon();
    MyPolygon mp2 = new MyPolygon(4);
    MyPolygon mp3 = new MyPolygon(5);
    MyPolygon mp4 = new MyPolygon(6);
    System.out.println("Polygon 1 has " + mp1.getSides()
            + " sides, angles total " + mp1.getSumOfAngles());
    System.out.println("Polygon 2 has " + mp2.getSides()
            + " sides, angles total " + mp2.getSumOfAngles());
    System.out.println("Polygon 3 has " + mp3.getSides()
            + " sides, angles total " + mp3.getSumOfAngles());
    System.out.println("Polygon 4 has " + mp4.getSides()
            + " sides, angles total " + mp4.getSumOfAngles());
    System.out.println("There are " + MyPolygon.getTotalSides()
            + " total sides");

}
}

class MyPolygon {
double getSides;

MyPolygon() {
    getSides = 3;
}

static double getTotalSides() {

    return 0;
}

double getSides() {
    // TODO Auto-generated method stub
    return getSides;
}

MyPolygon(double newGetSides) {
    getSides = newGetSides;
}

double getSumOfAngles() {
    return ((getSides - 2) * 180);
}

void setGetSides(double newGetSides) {
    getSides = newGetSides;
}

Answer 1

如果您确实需要一个方法，您可以使用可变参数( variable arity arguments )来实现此目的:

static double getTotalSides(MyPolygon... polygons) {
  double x = 0;

  for (MyPolygon p: polygons)
  {
   x+= p.getSides();
  }
   return x;
}

然后像这样调用:

System.out.println("There are " + MyPolygon.getTotalSides(mp1,mp2,mp3,mp4)
            + " total sides");

或者创建一个数组

MyPolygon myPolygons = new MyPolygon [4];
myPolygons [0] = mp1;
myPolygons [1] = mp2;
myPolygons [2] = mp3;
myPolygons [3] = mp4;
System.out.println("There are " + MyPolygon.getTotalSides(myPolygons)
            + " total sides");

但是，更好的解决方案是从一开始就将多边形存储在数组/列表中，然后将整个数组/列表传递给方法，执行循环并返回结果。但请注意，列表和数组是不同的，因此，您需要相应地修改方法签名。