java - 如何将用户字符串输出存储到 String[] 数组中

Question

所以我有一个私有(private) String[] teamName;。我想要做的只是使用用户输出的字符串并将该字符串存储到 String[] teamName; 中。我正在使用 teamName[team] 并将其等于 = Keyboard.nextLine()，这样做会给我一个 nullexpection 错误。为什么？

所以这就是我所拥有的......

私有(private)字符串[]团队名称；//包含每个团队的条目

public void enterInData( )
{
    Scanner keyboard = new Scanner(System.in);

    System.out.println("Enter number of teams:");
    numberOfTeams = keyboard.nextInt( );

    System.out.println("Enter number of weeks:");
    numberOfWeeks = keyboard.nextInt( );

    scores =new int [numberOfTeams][numberOfWeeks];
    // ************** Fill in Code ***************
    // Allocate array memory for teamName to store the team names.
    // Allocate array memory for scores (2 dimensional array) to store a 
    // score for each team for each week. 
        teamName = new String[4];
    for (int team = 0; team < numberOfTeams; team++)
    {
        System.out.println("Enter team name");

        // ************* Fill in Code **************
        // Read in Team name and store it in teamName
        teamName = new String[team];
        teamName[team] =  keyboard.nextLine();



        for (int week = 0; week < numberOfWeeks; week++)
        {
            System.out.println("Enter score for team "+ teamName[team]);
            System.out.println("on week number " + (week+1));
            // ************  Fill in Code ***************
            // Read in a score and store it in the proper spot in the scores array
         scores[team][week] = keyboard.nextInt();
         }

}

Answer 1

您会得到一个空指针异常，因为当您在循环内重新声明 stringTeam 数组时(根本不需要)，您正在使用变量 team 作为数组的大小。在循环的第一次迭代中，该变量的值为 0。您创建一个维度为 0 的空数组。您想要的只是分配一个字符串:

teamName[team] = keyboard.nextLine();