将信息存储到另一个类的数组中

Question

我已经为此工作了一段时间，但似乎无法理解。 我需要将用户输入内容从另一个对象存储到数组中，但无法使其正常工作。 我不确定它是我的构造函数还是缺少什​​么，但是可以提供任何帮助

这是输出程序

    public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       System.out.println("Enter   'p' to create a polygon");
       String in = sc.next();

    if (in.equals("p")) {
        System.out.println("How many sides?");
        int numSides = sc.nextInt();
        int side=0; 

        Polygon ps;
        for (int i = 1; i <= numSides; i++) {

            System.out.println("Enter the length of side " + i);
            side = sc.nextInt();
             ps = new Polygon(side);

        }
         ps = new Polygon(side);

这是另一个类的构造函数

public class Polygon {
    protected int[] sideLengths;


public Polygon(int sides){
    sideLengths= new int[sides];

}

Answer 1

你需要做

ps=new Polygon(numSides+1); //adding 1 because for-loop starts with index 1
for (int i = 1; i <= numSides; i++) {

      System.out.println("Enter the length of side " + i);
      side = sc.nextInt();
      ps[i]=side;

}

通过这样做，我们将用户输入的“边”值分配给数组中的特定索引。

希望这可以帮助！

祝好运

Answer 2

我了解您的程序的方式我认为您正在寻找这种逻辑

if (in.equals("p")) {
            System.out.println("How many sides?");
            int numSides = sc.nextInt();
            int side = 0;

            Polygon ps;
            int sideLengths[] = new int[numSides];// array to store length of  polygon of sides `numSides`
            for (int i = 1; i <= numSides; i++) {

                System.out.println("Enter the length of side " + i);
              sideLengths[i-1] = sc.nextInt();// creating array to store lengths


            }
            ps = new Polygon(sideLengths);// generating your pollygon by sending the array

        }

而您的Polygon类应该看起来像这样

    class Polygon {

            protected int[] sideLengths;// storing the lengths of all sides

            public Polygon(int dimensions[]) {
                sideLengths = dimensions ;

            }
        }

Answer 3

 public static void main(String[] args) {
       Scanner sc = new Scanner(System.in);
       System.out.println("Enter   'p' to create a polygon");
       String in = sc.next();


            if(in.equalsIgnoreCase("p")) {
                Integer sides[];
                System.out.println("How many sides?");
                int numSides = sc.nextInt();
                int side=0; 
                if(numSides>0){
                    sides = new Integer[numSides];
                }
                Polygon ps;
                for (int i = 1; i <= numSides; i++) {

                    System.out.println("Enter the length of side " + i);
                    side = sc.nextInt();
                    sides[i] = side;

                }

                ps = new Polygon(sides);
            }
     }

public class Polygon {
    private Integer[] sides;
    public Polygon(Integer[] sides){
        this.sides = sides;
    }
}

现在，我们创建了一个边长为大小的数组，并将该数组作为参数传递给构造函数以初始化Polygon的对象

Answer 4

它应该像

public static void main(String[] args) {
   Scanner sc = new Scanner(System.in);
   System.out.println("Enter   'p' to create a polygon");
   String in = sc.next();

if (in.equals("p")) {
    System.out.println("How many sides?");
    int numSides = sc.nextInt();
    int side=0; 

    Polygon ps = new Polygon(numSides);
    for (int i = 1; i <= numSides; i++) {

        System.out.println("Enter the length of side " + i);
        side = sc.nextInt();
        ps.addSide(side, i-1);
         //ps = new Polygon(side);

    }
     //ps = new Polygon(side);
}}}

和多边形类一样

public class Polygon {
    protected int[] sideLengths;


    public Polygon(int sides){
        sideLengths= new int[sides];

    }
    public void addSide(int side, int index){
        sideLengths[index] = side;
    }
}

Answer 5

您正确地调用了构造函数，但是在for循环结束之后，您再次创建了Polygon的新实例并将其分配给ps。 创建一个int数组或Integer的ArrayList，并在for循环结束之前在其中存储每个Polygon边长的实例。

ArrayList<int> psListpsSideLengthList = new ArrayList<int>;
for (int i = 1; i <= numSides; i++) {

    System.out.println("Enter the length of side " + i);
    side = sc.nextInt();
     psListpsSideLengthList.add(side);

}