Question

好的，所以我正在编写这个程序，其中数组的一部分设置为数组另一部分的值。相关代码是（顺便说一下是第50行）：

variables[(program[1])+2]=inputs[0];

这里是数组初始化的地方：

int[] variables;
    variables=new int[10000];

程序数组：

int[] program;
    program=new int[10000];

输入数组：

int[] inputs;
    inputs=new int[9];

当我运行它时，会产生错误：

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
at Central.main(Central.java:50)

有什么想法吗？提前谢谢。

好的，这是整个代码：

import java.util.Random;

import java.util.Scanner;

public class Central {

public static void main(String[] args) {
    int[] inputs;
    inputs=new int[9];
    int[] outputs;
    outputs=new int [9];
    int[]results;
    results=new int [10000];
    int[] program;
    program=new int[10000];
    int[][] random;
    random=new int[100][100];
    int[] bestProgram;
    bestProgram=new int[10000];
    int[] bestVariables;
    bestVariables=new int [10000];
    int[] variables;
    variables=new int[10000];
    int[][] bestRandom;
    bestRandom=new int [100][100];
     Scanner sc = new Scanner(System.in);
     inputs[0]=sc.nextInt();
     inputs[1]=sc.nextInt();
     inputs[2]=sc.nextInt();
     inputs[3]=sc.nextInt();
     inputs[4]=sc.nextInt();
     inputs[5]=sc.nextInt();
     inputs[6]=sc.nextInt();
     inputs[7]=sc.nextInt();
     outputs[0]=sc.nextInt();
     outputs[1]=sc.nextInt();
     outputs[2]=sc.nextInt();
     outputs[3]=sc.nextInt();
     outputs[4]=sc.nextInt();
     outputs[5]=sc.nextInt();
     outputs[6]=sc.nextInt();
     outputs[7]=sc.nextInt();
    program=createProgram(program);
    random=createRandom(random, program);
    for (int g=0;g<=100;g++) {
    random=createRandom(random,program);
    variables=new int [program[1]+2];
    variables[program[1]+1]=1;
    results[0]=run (program,variables,random);
    variables[(program[1])+2]=inputs[0];
    results[1]=run (program,variables,random);
    variables[program[1]+2]=inputs[1];
    results[2]=run (program,variables,random);
    variables[program[1]+2]=inputs[2];
    results[3]=run (program,variables,random);
    variables[program[1]+2]=inputs[3];
    results[4]=run (program,variables,random);
    variables[program[1]+2]=inputs[4];
    results[5]=run (program,variables,random);
    variables[program[1]+2]=inputs[5];
    results[6]=run (program,variables,random);
    variables[program[1]+2]=inputs[6];
    results[7]=run (program,variables,random);
    variables[program[1]+2]=inputs[7];
    bestProgram=findBestProgram(program, variables, random, bestProgram, bestVariables, bestRandom, inputs, outputs, results);
    }
    for (int i=0;i<=program[0];i++)
    {
    System.out.println(bestProgram[i]);
    }
    }
    public static int[] createProgram(int[] program) {
    program[0]=randInt(1,50);
    program[1]=randInt(1,3);
    for (int i=2;i<=program[0];i++)
    {
    program[i]=randInt(1,3);
    }
    return program;
    }
    public static int run(int[] program, int[] variables,int[][] random)
    {
    for (int i=2;i<=program[0];i++) {
    switch (program[i]) {
    case 1: variables[random[i][0]]=variables[random[i][1]]+variables[random[i][2]];
    break;
    case 2: variables[(random[i][0])]=(variables[(random[i][1])])-(variables[random[i][2]]);
    break;
    default: System.out.println("This error really shouldn't happen ever");
    }
    }
    return variables[0];
    }
    public static int[][] createRandom(int[][] random, int[] program)
    {
    for (int i=0;i<=program[0];i++)
    {
    for (int a=0; a<=2;a++)
    {
    random[i][a]=randInt(1,3);
    }
    }
    return random;
    }
    public static int[] findBestProgram(int[] program, int[] variables, int[][] random,int[] bestProgram, int[]bestVariables, int[][]bestRandom, int[] inputs, int[] outputs, int[] results)
    {
    int bestProgramResult=run(bestProgram, bestVariables,bestRandom);
    int[] resultz;
    resultz= new int [10000];
    resultz[0]=Math.abs(results[0]-outputs[0]);
    resultz[1]=Math.abs(results[1]-outputs[1]);
    resultz[2]=Math.abs(results[2]-outputs[2]);
    resultz[3]=Math.abs(results[3]-outputs[3]);
    resultz[4]=Math.abs(results[4]-outputs[4]);
    resultz[5]=Math.abs(results[5]-outputs[5]);
    resultz[6]=Math.abs(results[6]-outputs[6]);
    resultz[7]=Math.abs(results[7]-outputs[7]);
    int programResult=results[0]+results[1]+results[2]+results[3]+results[4]+results[5]+results[6]+results[7];
    if (programResult<bestProgramResult)
    {
    bestProgramResult=programResult;
    for (int i=0;i<=program[0];i++)
    {
    bestProgram[i]=program[i];
    bestVariables[i]=variables[i];
    bestRandom[i]=random[i];
    }
    }
    return bestProgram;
    }
    public static int randInt(int min, int max) {
        Random rand = new Random();
        int randomNum = rand.nextInt((max - min) + 1) + min;
        return randomNum;
    }
    }
    //1: _=_+_
    //2: _=_-1

Answer 1

您收到异常是因为您尝试访问的索引不受数组大小的限制。换句话说，program[1] + 2大于9999，这是变量数组中最大的索引号。

Answer 2

问题出在以下几行：variables=new int [program[1]+2]; 基本上，如果我理解的是正确的，你已经重新初始化变量数组并将其大小更改为5.然后，在第50行：variables[(program[1])+2]=inputs[0];你试图访问数组的第5个索引数组由0到4之间的索引定义。

当数组有足够的空间时，Java数组索引超出界限错误

2 个答案: