lab3.Lab3.readTestScore(Lab3.java:93) lab3.Lab3.main(Lab3.java:25)线程java.lang.ArrayIndexOutOfBoundsException: 0异常

Question

package lab3;


import java.util.Scanner;

public class Lab3 
{

    static int n;
    static double testScores[] = new double[n];
    public static void main(String[] args) 
    {
       Scanner input = new Scanner(System.in);
       int studentID;

       System.out.println("Enter student ID: ");
       studentID = input.nextInt();
       System.out.println("Enter number of test scores");
       n = input.nextInt();

       readTestScore(n);

      //double[] testarray = readTestScore(n);
      //System.out.println("Test Scores are:" + testarray);

    }
    public char getLetterGrade(double score)
    {
        char letter;
        if(score >= 90)
        {
            printComment('A');
            letter = 'A';
        }
        if(score >= 80)
        {
            printComment('B');
            letter = 'B';
        }   
        if(score >= 70)
        {
            printComment('D'); 
            letter = 'C';
        }   
        else if(score >= 60)
        {
            printComment('D');
            letter = 'D';
        }
        else if(score < 60)
            printComment('F');
            letter = 'F';

        return letter;
    }
    static void printComment(char grade)
    {
        if(grade == 'A')
        System.out.println("COMMMENT\t\t\t:\t" + "Very Good!");
        if(grade == 'B')
        System.out.println("COMMMENT\t\t\t:\t" + "Good!");
        if(grade == 'C')
        System.out.println("COMMMENT\t\t\t:\t" + "Satisfactory.");
        if(grade == 'D')
        System.out.println("COMMMENT\t\t\t:\t" + "Needs Improvement.");
        if(grade == 'F')
        System.out.println("COMMMENT\t\t\t:\t" + "Poor.");


    }
    static void printTestResults(double []testList)
    {

     for(int i = 0; i < testList.length; i++)
     {

         System.out.println("Test Score\t\t\t" + "Letter Grade\t\t\t" + "Comment\t\t\t");
        System.out.println(testScores[i] + "\t\t\t" );//+ getLetterGrade(score) + "\t\t\t" + printComment(grade));

     }  
    }
    static double[] readTestScore(int size)
    {
        Scanner input = new Scanner(System.in);

        int i =0;
        System.out.println("Enter Test Scores:\t");
        for(i = 0; i<n; i++)
        {
        testScores[i] = input.nextDouble();
        }
       testScores[i] /=n;
       System.out.println("these are test scores: " + testScores);
        return (testScores);
    }   
}

Answer 1

因为这个原因

static int n;
static double testScores[] = new double[n];

数组被设置为默认大小int ie 0，这会在方法中给出错误