我对Java相当陌生，有人能帮我提高代码的效率吗？

这段代码的目标是获取关于四边形两侧的用户输入，并输出形状的周长和面积。我对Java语言非常陌生，因此，这些错误最有可能通过一两次小的编辑得到解决。如果有Java编程经验的人能帮助我，我将不胜感激：）

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它很好，几乎没有错误。下面是代码的可编译版本。如果你有任何问题，请告诉我

    import java.util.Scanner;

    public class Quadrilateral {
      public static void main(String[] args) {
        double area, perimeter;
        String answer;

        Scanner ans1 = new Scanner(System.in);
        System.out.println("Is your desired shape 2-dimensional or 3-dimensional: 2d or 3d");
        answer = ans1.next();

        switch (answer) {
          case "2d":
            System.out.println("Good, you shall be allowed to continue.");
            break;

          case "3d":
            System.out.println("You are bad and should feel bad.");
            System.exit(1);
        }

        Scanner keys = new Scanner(System.in);

        System.out.print("Enter your first side length: \n");
        double side1 = keys.nextDouble();

        System.out.print("Enter your second side length: \n");
        double side2 = keys.nextDouble();

        System.out.println("The perimeter of your desired shape is: \n" + perimeter(side1, side2));
        System.out.println("The area is: \n" + area(side1, side2));

      }

      public static double area(double side1, double side2) {
        return side1 * side2;
      }

      public static double perimeter(double side1, double side2) {
        return ((2 * side1) + (2 * side2));
      }
    }

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您需要了解变量的范围。您可以声明

双面积、周长在
main
内部，这意味着这些变量是main的本地变量，这意味着它们不再存在于main之外的任何地方

您需要在periment方法内部声明
双周长
，然后为area返回它，反之亦然

或者，您不能在这些方法中使用变量，而只是简单地
返回side1*side2
您说您得到错误是什么？请清楚地描述错误是什么，如果您能够构建程序，请描述您如何测试它，以及观察到的和预期的输出是什么。如果需要，您可以参考
    import java.util.Scanner;

    public class Quadrilateral {
      public static void main(String[] args) {
        double area, perimeter;
        String answer;

        Scanner ans1 = new Scanner(System.in);
        System.out.println("Is your desired shape 2-dimensional or 3-dimensional: 2d or 3d");
        answer = ans1.next();

        switch (answer) {
          case "2d":
            System.out.println("Good, you shall be allowed to continue.");
            break;

          case "3d":
            System.out.println("You are bad and should feel bad.");
            System.exit(1);
        }

        Scanner keys = new Scanner(System.in);

        System.out.print("Enter your first side length: \n");
        double side1 = keys.nextDouble();

        System.out.print("Enter your second side length: \n");
        double side2 = keys.nextDouble();

        System.out.println("The perimeter of your desired shape is: \n" + perimeter(side1, side2));
        System.out.println("The area is: \n" + area(side1, side2));

      }

      public static double area(double side1, double side2) {
        return side1 * side2;
      }

      public static double perimeter(double side1, double side2) {
        return ((2 * side1) + (2 * side2));
      }
    }