如何找到最大值的索引？

Posted 2023-02-25

【中文标题】如何找到最大值的索引？

【英文标题】：How to find the maximum's index?

【发布时间】：2018-05-05 09:09:05

【问题描述】：

我在这里遇到了这个问题。索引是 int，但程序让我翻倍。我找不到问题。有很多几何形状，它们有中心坐标和边长。我必须计算面积和环境的差异，然后选择最大数字的索引。

/主类

package beadandó;

import java.io.FileNotFoundException;

public class Main     
    public static void main(String[] args) 
        Geom geom = new Geom();
        try 
            geom.read("input.txt");
            System.out.println(geom.MaxKiv());
         catch (FileNotFoundException ex) 
            System.out.println("File not found!");
            System.exit(-1);
         catch (InvalidInputException ex) 
            System.out.println("Invalid input!");
            System.exit(-1);
        
    

/getDifference

package beadandó;

import java.util.ArrayList;


public abstract class GeometricShape 
    private Point center;
    double length;
    private ArrayList<Double> difference;

    public GeometricShape( Point center, double length) 
        this.center = center;
        this.length = length;
        difference = new ArrayList<>();
    

    public void setCenter(Point center) 
        this.center = center;
    

    public void setLength(double length) 
        this.length = length;
    

    public Point getCenter() 
        return center;
    

    public double getLength() 
        return length;
    

    public ArrayList<Double> getDifference() 
        return difference;
    

    public abstract double doMath();

/MaxKiv 是最大值查找器

package beadandó;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Scanner;

public class Geom 

    private final ArrayList<GeometricShape> geometricShapes;

    public Geom() 
        geometricShapes = new ArrayList<>();
    

    public void read(String filename) throws FileNotFoundException, InvalidInputException 
        Scanner sc = new Scanner(new BufferedReader(new FileReader(filename)));
        int number = sc.nextInt();
        while (sc.hasNext()) 
            GeometricShape geometricShape;
            int kind = sc.nextInt();
            double x = sc.nextDouble();
            double y = sc.nextDouble();
            Point center = new Point(x, y);
            double length = sc.nextDouble();
            switch (kind) 
                case 0:
                    geometricShape = new Circle(center, length);
                    break;
                case 3:
                    geometricShape = new Triangle(center, length);
                    break;
                case 4:
                    geometricShape = new Square(center, length);
                    break;
                case 6:
                    geometricShape = new Hexagon(center, length);
                    break;
                default:
                    throw new InvalidInputException();
            
            geometricShapes.add(geometricShape);
        
    

    public double MaxKiv() 
        double max = 0;
        int index =0;
        for (int i = 0; i < geometricShapes.size(); ++i) 
            if (max <geometricShapes.get(i).doMath()) 
                max = geometricShapes.get(i).doMath();
                index=i;
            
        
        return index;
    

/计算差异（有很多形状，这是其中之一）

package beadandó;

import static java.lang.Math.sin;

public class Hexagon extends GeometricShape 

    public Hexagon(Point center, double length) 
        super(center, length);
    

    @Override
    public double doMath()         
        double circumfence=(3*(length*length)*sin(60));
        double district=(6*length);
        double difference=(circumfence-district);
        return difference;
    

【问题讨论】：

永远不要这样设计你的问题。发布您的努力以获得快速帮助。

Why is “Can someone help me?” not an actual question?

对不起。我发布了代码。

我认为你想要index=1; 而不是这一行：index = i;。

CodeMatrix 将代码编辑为 1。它是 i。 :D

【参考方案1】：

您已声明：

public double MaxKiv() 

所以是的，显然这会给你一个double。要获取int，只需更改声明以返回int：

public int MaxKiv() 

您返回的值index 已经声明为int，所以这应该足以解决您的问题。