不知道为什么我在 java.lang.ArrayIndexOutOfBounds "main"线程中有此错误异常异常：0

Question

这是我的代码

import java.util.Scanner;
public class Input {
    static class General_Inputs{
        static int Num_Of_Ppes;
        static int Num_Of_States;
        static int Num_Of_Analysis_Years;
        static int Number_Decision_Variables;
        static int Num_objectives;
        static int Num_Constraints;
        static int[] Num_Alt_Decision_variable=new int[Number_Decision_Variables];  
    }
public static double[][] Get_Inputs(){
    Scanner State_Vector=new Scanner(System.in);
    System.out.println("Enter the number of Decision_Variables");
    General_Inputs.Number_Decision_Variables=State_Vector.nextInt();
    for(int Num=0;Num<General_Inputs.Number_Decision_Variables;Num++){
        System.out.println("Enter the number of Alternatives for Decision Variable "+(Num+1));
        General_Inputs.Num_Alt_Decision_variable[Num]=State_Vector.nextInt();
    }
    State_Vector.close();
    return Current_Cond_State_Cof_lngth;
}
public static void main(String args[]){
    double[][] input=Input.Get_Inputs();

输入如下所示：输入Decision_Variables数3输入决策变量 1 的备选方案数2这应该进行三次，但它在第一个决策变量处停止并给出以下错误，我不确定问题出在哪里。我知道此错误意味着数组"Num_Alt_Decision_variable"的大小为零，但为什么会这样 我在上面定义了这个数组，我真的尝试了很多搜索，但找不到原因 非常感谢任何帮助，提前感谢。

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
    at Input.Get_Inputs(Input.java:48)
    at Input.main(Input.java:66)

Answer 1

    static int Number_Decision_Variables; // this is 0 here
    static int Num_objectives;
    static int Num_Constraints;
    // and it's still 0 here.
    static int[] Num_Alt_Decision_variable=new int[Number_Decision_Variables]; 

Number_Decision_Variables在声明Num_Alt_Decision_variable时为 0。所以你的数组大小为 0，这是一个不可用的数组。我建议您使用非 0 数字初始化它。

在此行之后初始化数组：

General_Inputs.Number_Decision_Variables=State_Vector.nextInt();

获得Number_Decision_Variables变量的实际值后。

顺便说一句，您将需要学习和使用Java命名约定。变量名都应以小写字母开头，而类名应以大写字母开头。

Answer 2

这是我可以解决的答案

import java.util.Scanner;
public class Input {
    static class General_Inputs{
        static int Num_Of_Ppes;
        static int Num_Of_States;
        static int Num_Of_Analysis_Years;
        static int Number_Decision_Variables;
        static int Num_objectives;
        static int Num_Constraints;
        static int[] Num_Alt_Decision_variable;  
    }
public static double[][] Get_Inputs(){
    Scanner State_Vector=new Scanner(System.in);
    System.out.println("Enter the number of Decision_Variables");
    General_Inputs.Number_Decision_Variables=State_Vector.nextInt();
General_Inputs.Num_Alt_Decision_variable=new int[General_Inputs.Number_Decision_Variables]
    for(int Num=0;Num<General_Inputs.Number_Decision_Variables;Num++){
        System.out.println("Enter the number of Alternatives for Decision Variable "+(Num+1));
        General_Inputs.Num_Alt_Decision_variable[Num]=State_Vector.nextInt();
    }
    State_Vector.close();
    return Current_Cond_State_Cof_lngth;
}
public static void main(String args[]){
    double[][] input=Input.Get_Inputs();