java - ArayIndexOutOfBoundsException 不起作用

Question

我的代码有问题:

import java.io.*;
import java.util.*;
public class goTooFar {
    public static void main(String[] a){

        int i =4;
        int[] ar = new int[i];
        int n = i;
        Scanner sc = new Scanner(System.in);

        System.out.println("Enter the size of an array: ");
        try {
            n = sc.nextInt();
        } catch(ArrayIndexOutOfBoundsException e) {
            System.out.println("Now you have gone too far");
        }


        System.out.println("Enter " + n + " elements of an array: ");
        for (i = 0; i <= n; i++) {
            try {
                ar[i] = sc.nextInt();
            } catch(ArrayIndexOutOfBoundsException e) {
                e.printStackTrace();
                System.out.println("Now you have gone too far");
            }
        System.out.println("Output Numbers: ");
            for (i = 0; i <= n; i++) {
                System.out.println(ar[i]);
            }
        }
    }
}

我有这样的输入:

> Enter the size of an array: 
7

> Enter 7 elements of an array: 
1 4 2 5 3 9 0 7

但是，事实是这样的:

>Output Numbers: 
1
0
0
0
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
    at goTooFar.main(goTooFar.java:31)

我可以做什么来解决这个问题？有人能帮我吗？多谢。 :)

Answer 1

将数组的长度初始化为 4:

int i =4;
int[] ar = new int[i];

因此，当您输入较长的数组长度时，您会收到 ArrayIndexOutOfBoundsException。

您需要在从用户处获取长度后创建数组:

System.out.println("Enter " + n + " elements of an array: ");
ar = new int[n]; // initialize a new array
for(i = 0; i < n; i++){ // n is not a valid index for an array of length n

同时更改另一个循环的范围

    for(i = 0; i <= n; i++){
        System.out.println(ar[i]);
    }

至

    for(i = 0; i < n; i++){
        System.out.println(ar[i]);
    }