Question

简而言之，实现一个循环，使用户可以选择数组的字符串元素的索引值，然后将选择返回给用户并验证用户输入。

我注意到该循环由于一个错误而关闭的错误，因此包含了“ <=”“ |”。我已更改为一个数组初始化器，它不那么容易出错。循环仅打印出索引值，而不打印出字符串。我已经将数组更改为数组类，并得到了错误。 “课程构造函数无法应用于声明的类型，实际参数和表单参数的长度不同”，我研究了Javadoc声明。并看到在构造函数中这样声明。 = new ArrayList（Length）或类似的东西，但我不想覆盖任何内容。我试图在NetBeans中获得支持以解决该问题，但是在实现代码时，却得到了NetBeans支持为数组的第一个元素完全实现的代码

我想有效运行的循环代码

Lesson[] lessonList = new Lesson [4];


lessonList[0] =  new Lesson ("Zumba");
lessonList[1] = new Lesson("Spin");
lessonList[3] = new Lesson("Yoga");
lessonList[4] = new Lesson("BodySculpt");

for(int count = 0; count <= lessonList.length; | count++){
    System.out.println((count + 1) + ". " + lessonList[count]);
}

System.out.println("Please select ");
int selection = sc.nextInt();
selection -= 1;

if(selection >lessonList.length | selection < 0) {
    System.out.println(" You have entered invalued value.");
    lessonsList();
    System.out.println("Can you please re-enter selection  .");
} 

return selection;

在Lesson类中，错误的发生与构造函数有关，错误“ Lesson构造函数无法应用于声明的类型，实际参数和表单参数的长度不同”

public class Lesson {

    private String lessonTitle;
    private String lessonDate;
    private int lessonPrice;
    private Rating rating;

    public void Lesson (String title) {
        this.setTitle(title);
        rating = new Rating();
    }

    public void lesson (String zumba, 
                        String spin, 
                        String yoga, 
                        String bodysculpt ) 
    { 

        /// tried declaring recieve errors 
    }

    public Lesson() {
        this.lessonTitle = "Udentified";
        this.rating = new Rating();
    }

预期的结果将消除循环中的缺陷以及构造函数的基本解决方案提示。所以我可以处理下一个元素

Answer 1

import java.util.*;
public class Tester {
    public static void main(String [] args) {
        Scanner sc = new Scanner(System.in);
                Lesson [] lessonList = new Lesson [4];
                lessonList[0] =  new Lesson ("Zumba", "Monday & Wednesday", 100, 3.4);
                lessonList[1] = new Lesson("Spin", "Tuesday & Thursday", 80, 3.9);
                lessonList[2] = new Lesson("Yoga", "Sunday", 83, 4.0);
                lessonList[3] = new Lesson("BodySculpt", "Friday and Saturday", 90, 3.85);


                for(int count = 0; count < lessonList.length; count++){
                    System.out.println((count + 1) + ". " + lessonList[count]); 
                }

                System.out.println("Please select between 1 - 4 for the lessons ");
                int selection = sc.nextInt();
                selection -= 1;
                while(selection >lessonList.length | selection < 0) {
                    System.out.println("Can you please re-enter selection  .");
                    selection = sc.nextInt();
                }
                System.out.println((selection + 1) + ". " + lessonList[selection]); 
    }
}

public class Lesson {

    private String lessonTitle;
    private String lessonDate;
    private double lessonPrice;
    private double rating;

    public Lesson() { //default constructor
        this.lessonTitle = null;
        this.lessonDate = null;
        this.lessonPrice = 0;
        this.rating = 0;
    }

    public Lesson (String title, String date, double price, double rate) { //second constructor
        this.lessonTitle = title;
        this.lessonDate = date;
        this.lessonPrice = price;
        this.rating = rate;
    }

**//When you want to print a class, you must need a toString method defined right**

    public String toString () {
        return "Lesson Title: " + this.lessonTitle + ", Lesson Date: " + this.lessonDate + ", $" + this.lessonPrice + ", Rate: " + this.rating;
    }

}

如何减少循环的混乱程度以及如何实现循环

1 个答案: