java - 如果有人可以处理这个错误代码，我会很高兴，找不到问题所在

Question

我的程序获取一个 worker 30 天每天一小时和一分钟的开始时间和结束时间，然后找到他工作最长的一天并将其设置为要显示的输出。问题(我认为)似乎出在 for 循环中，这是循环部分:

for (ti=1; ti<=3; ti++) {

            System.out.println("Please enter the hours and minutes you started by this order.");
            double hours1 = reader.nextDouble();
            double mins1 = reader.nextDouble();

            System.out.println("Please type the time you finished in hours and minutes by this order.");
            double hours2 = reader.nextDouble();
            double mins2 = reader.nextDouble();

            double total = difference(hours1, mins1, hours2, mins2);

            tdays.add(total);

            if (tdays.get(ti) > tdays.get(ti - 1)) {
                big = tdays.get(ti);
                tday = ti;
            }

        }

错误代码:

    at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:64)
    at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Preconditions.java:70)
    at java.base/jdk.internal.util.Preconditions.checkIndex(Preconditions.java:248)
    at java.base/java.util.Objects.checkIndex(Objects.java:373)
    at java.base/java.util.ArrayList.get(ArrayList.java:425)
    at Main.main(Main.java:24)

完整代码:```import java.util.*;公共(public)类主要{

static Scanner reader = new Scanner(System.in);
public static void main(String[] args) {

    ArrayList<Double> tdays = new ArrayList<>();
    int ti, tday=0;
    double big=0;
    for (ti=1; ti<=3; ti++) {

        System.out.println("Please enter the hours and minutes you started by this order.");
        double hours1 = reader.nextDouble();
        double mins1 = reader.nextDouble();

        System.out.println("Please type the time you finished in hours and minutes by this order.");
        double hours2 = reader.nextDouble();
        double mins2 = reader.nextDouble();

        double total = difference(hours1, mins1, hours2, mins2);

        tdays.add(total);

        if (tdays.get(ti) > tdays.get(ti - 1)) {
            big = tdays.get(ti);
            tday = ti;
        }

    }

    System.out.println("The worker has worked " + big + " hours on day number " + tday + ".");

}

public static double convertMin (double hours, double minutes) {

    double totalmin;
    hours = hours * 60;
    totalmin = hours + minutes;

    return totalmin;

}

public static double difference(double mins1, double hours1, double mins2, double hours2) {

    double total1 = convertMin(hours1, mins1);
    double total2 = convertMin(hours2, mins2);

    return total2 - total1;

}

}

Thanks for any help!

Answer 1

您的问题是您只向列表添加一个元素，但随后您尝试访问索引“1”(这将是第二个元素)

我认为您可以通过添加检查是否 tdays.size() > 1 (或类似的内容)来解决此问题

我已将各行分开以向您显示导致错误的部分。

tdays.add(total);

Double a = tdays.get(ti); // this tries to access index 1, but there is only one element
Double b = tdays.get(ti - 1);
if (a > b) {
    big = tdays.get(ti);
    tday = ti;
}