4、函数式编程语言及设计策略解析

函数式编程语言及设计策略解析

1. 类的示例

以 Java 语言为例，来看一个类的示例：

public class Rectangle extends Shape {
    private float length;
    private float width;
    public Rectangle (float length, float width) {
        this.length = length;
        this.width = width;
    }
    public float getLength () {
        return length;
    }
    public float getWidth () {
        return width;
    }
    public float perimeter () {
        perimeter (length, width);
        // just in case the class calculation changes
    }
    public static float perimeter (float length, float width) {
        return (2 * (length + width));
    }
    public float area () {
        area (length, width);
        // just in case the class calculation changes
    }
    public