chapter 4

src/chapter4/demo45/Main.java

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+package chapter4.demo45;
+
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        // 处理用户输入
+        Scanner sc = new Scanner(System.in);
+
+        while(true) {
+            // 打印菜单
+            ShapeCalculate.printMenu();
+            int select = sc.nextInt();
+            // 判断用户选项
+            switch (select) {
+                case 1: // 圆形
+                    System.out.print("请输入圆形的半径：");
+                    double radius = sc.nextDouble();
+                    Shape circle = new Circle(radius);
+                    ShapeCalculate.printArea(circle);
+                    ShapeCalculate.printPerimeter(circle);
+                    break;
+                case 2: // 长方形
+                    System.out.print("请输入长方形的长和宽：");
+                    double length = sc.nextDouble();
+                    double width = sc.nextDouble();
+                    Shape rectangle = new Rectangle(length, width);
+                    ShapeCalculate.printArea(rectangle);
+                    ShapeCalculate.printPerimeter(rectangle);
+                    break;
+                default:
+                    System.out.println("输入错误，请重新选择");
+                    ShapeCalculate.printMenu();
+                    break;
+            }
+            // 询问用户是否继续
+            System.out.println("继续计算？（Y / N）");
+            String answer = sc.next();
+            if ("N".equalsIgnoreCase(answer)) { // 无论大小写，都识别
+                break;
+            }
+        }
+        System.out.println("感谢您的使用，再见！");
+        sc.close();
+    }
+
+
+
+}