java - 更改 for 循环内全局变量的值

Question

我正在为学校作业创建一个小程序，人们可以在其中输入他们的运行历史记录(跑的英里数、耗时)并查看他们潜在的 10K 配速和马拉松配速时间。显示步速后，会显示不同步速的表格。

我有一个全局变量(pace)，大多数计算都使用它运行，需要在 for 循环内更改它，但不会更新计算。

编辑:我知道这个程序写得不好，有很多东西可以压缩。然而，它可以工作并且将满足分配的参数。在 for 循环内部，变量“pace”需要在每次循环迭代时增加 30。

public class MarathonTime {

public static void main(String[] args) {

    String name;
    double distance;
    int hours, minutes, seconds;
    double pace;

    @SuppressWarnings("resource")
    Scanner scanner = new Scanner(System.in);

    System.out.print("What is your first name? ");
    name = scanner.next();
    System.out.print("How many miles did you run today? ");
    distance = scanner.nextDouble();
    System.out.print("How long did it take? Hours: ");
    hours = scanner.nextInt();
    System.out.print("Minutes: ");
    minutes = scanner.nextInt();
    System.out.print("Seconds: ");
    seconds = scanner.nextInt();

    pace = ((hours * 3600) + (minutes * 60) + seconds) / distance;
    double marathonPace = pace * 26.2;
    double tenKPace = pace * 6.2;

    int paceMinutes, paceSeconds;
    paceMinutes = (int) pace / 60;
    paceSeconds = (int) pace % 60;

    int marathonHours, marathonMinutes, marathonSeconds;
    marathonHours = (int) marathonPace / 3600;
    marathonMinutes = (int) (marathonPace % 3600) / 60;
    marathonSeconds = (int) marathonPace % 60;

    int tenKMinutes, tenKSeconds;
    tenKMinutes = (int) tenKPace / 60;
    tenKSeconds = (int) tenKPace % 60;

    System.out.println("Hello " + name);
    System.out.print("Your pace is "); timeFormatPace(paceMinutes, paceSeconds);
    System.out.println();
    System.out.print("At this rate your marathon time would be ");  timeFormatMarathon(marathonHours, marathonMinutes, marathonSeconds); 
    System.out.println();
    System.out.print("and your 10K time would be "); timeFormat10K(tenKMinutes, tenKSeconds);
    System.out.println();
    System.out.println("Good luck with your training!");
    System.out.println();

     for(int i = 1; i <= 10; i++){
            if(i == 1) {
                System.out.println("Pace \t\t 10K Time \t\t Marathon Time");
                i++;
            }
            if(i == 2) {
                System.out.println("------------------------------------------------------");
                i++;
            }
            // input the tablePaces into the calcs and print them as the format
            pace = (281 + (i*30));

            if (i >= 3 && i <= 10) {

            timeFormatPace(paceMinutes, paceSeconds); System.out.print("\t\t "); timeFormat10K(tenKMinutes, tenKSeconds); System.out.print("\t\t\t ");
            timeFormatMarathon(marathonHours, marathonMinutes, marathonSeconds);
            System.out.println();
            }
     }  
}

Answer 1

我认为这就是你想要做的(非常简洁):

public static void main(String[] args) {
    int pace = 100; // or initialise to whatever

    for(int i = 0; i < 10; i++) {
        // do something

        pace = pace + 30; // or equivalently, pace += 30
    }
}

将来，尝试将您的问题减少到 minimal, complete and verifiable example 。这样做的过程通常会帮助您自己解决问题，但至少对其他人来说也很容易。

此外，如果您知道您的程序写得不好，请修复它!写得好的、简洁的、模块化的程序更容易推理。凌乱、复杂的代码很困难。您会感谢自己花在调试上的时间更少，并且您也会获得更好的成绩。