java - 具有两个字符串的基本并行数组

Question

当我测试它时，它构建得很好。但是当我运行它时，只会出现介绍和用户输出问题(这是它应该做的)，但是当我输入答案时，会出现错误:

    Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 50
    at statecapitals.StateCapitals.main(StateCapitals.java:141)

现在我知道我是新手，但我认为错误是我的数组不对应，我不确定我做错了什么。任何帮助将不胜感激。这是我所拥有的:

    String[] stateName = new String[50];
    String[] capName = new String[50];

    int i;
    for(i=0; i < 50; i++)
    {
    stateName[0] = "Alabama";
    stateName[1] = "Alaska";
    .....
    capName[0] = "Montgomery";
    capName[1] = "Juneau";
    .....
    }

    boolean found = false;

    Scanner keyboard = new Scanner(System.in);
    System.out.println("This program is designed...");
    System.out.println("Please enter the name of a U.S. state (please enter capitalized):");
    stateName[i] = keyboard.nextLine();

    for(i=0; (!found) && (i < stateName.lenth); i++)
      if(stateName[i].matches(capName[i]) )
      System.out.print(The capital of " + stateName + " is " + capName);
      found = true;
        if(!found)
        System.out.println("The name you entered was not on the list.");

*更新和编辑:最麻烦的代码行是:

    stateName[i] = keyboard.nextLine();

感谢大家的帮助，我做了一些改变:

    int i;
    for(i=0; i < 49; i++)
    {
    stateName[i+1]
    .....
    capName[i+1]
    ...
    }

另外，我在底部的 for 循环中添加了大括号。现在，当我运行它时，它停在线上:

    if(capName[i].matches(stateName[i]) )

这次的错误是:

    Exception in thread "main" java.lang.NullPointerException
    at statecapitals.StateCapitals.main(StateCapitals.java:146)

再次感谢大家的意见。

Answer 1

由于 i 未初始化(在代码片段中)

stateName[i] = keyboard.nextLine();

应该是这样的:

searchState = keyboard.nextLine();

这种比较是没有意义的，因为它永远不会匹配(应该是上面的 searchState):

 if(stateName[i].matches(capName[i]) )