我的循环任务存在编码问题，更多信息如下

Question

我的任务是仅使用 for 循环和数学函数创建一个程序，该程序输入 N 辆汽车，每次迭代都会获取汽车到达终点所需的时间，最终输出需要是第一个到达终点的汽车，第二个，意味着两次最低的时间。

我创建了一个程序：

    public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    
    System.out.println("enter total cars: ");
    int cars = sc.nextInt();
    double first = 0, second = 0;
    int car1 = 1, car2 = 1;
    for (int i = 1; i <= cars; i++) {
        System.out.println("enter car number " + i + " speed:");
        double speed = sc.nextDouble();
        if (i == 1) {
            first = speed;
            second = speed;
        }   
        
        if (speed < first) {
            second = first;
            first = speed;
            car2 = car1;
            car1 = i;
        } else {
            
            if (speed < second) {
                car2 = i;
                second = speed; 
            }
            
    
        }
    

    }
    System.out.println("car number one is " + car1 +" with speed of " + first);
    System.out.println("car number two is " + car2 +" with speed of " + second);
}

}

我遇到的问题是如何启动第一个和第二个变量，因为它们不能设置为 0，因为我需要检查我获得的速度是否低于第一个或第二个。我可能在第一次迭代中尝试将第一和第二设置为速度以开始一些东西，但它仍然有错误，所以我想知道如何修复它？ 谢谢。

Answer 1

下面是下面的工作代码，它可以让用户输入任意数量的汽车，询问其所用时间，然后打印两个最低时间的汽车编号及其各自所用的时间：

public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    System.out.println("enter total cars: ");
    int totalCars = sc.nextInt();
    
    double firstPlaceTime = Double.MAX_VALUE, secondPlaceTime = Double.MAX_VALUE;
    int firstPlaceNumber = 0, secondPlaceNumber = 0;
    
    for (int i = 1; i <= totalCars; i++) {
        System.out.println("Enter car number " + i + " time:");
        double currentTime = sc.nextDouble();
        
        if (currentTime < firstPlaceTime) {
            secondPlaceTime = firstPlaceTime;
            secondPlaceNumber = firstPlaceNumber;
            firstPlaceTime = currentTime;
            firstPlaceNumber = i;
        }
        else if (currentTime < secondPlaceTime) {
            secondPlaceTime = currentTime;
            secondPlaceNumber = i;
        }
    }
    
    System.out.println("car number one is " + firstPlaceNumber +" with time of " + firstPlaceTime);
    System.out.println("car number two is " + secondPlaceNumber +" with time of " + secondPlaceTime);
}

重要的部分是您可以初始化时间使用 Double.MAX_VALUE 的 double 值来确保前 2 辆汽车始终替换初始值：

double firstPlaceTime = Double.MAX_VALUE, secondPlaceTime = Double.MAX_VALUE;

除此之外，代码确实具有令人困惑的变量名称。我使用了更长的、更有意义的名称，以使代码更容易理解。

运行示例：

enter total cars: 
4
Enter car number 1 time:
50
Enter car number 2 time:
30
Enter car number 3 time:
40
Enter car number 4 time:
60
car number one is 2 with time of 30.0
car number two is 3 with time of 40.0

Answer 2

那么会是这样的事情吗？

public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    System.out.println("enter total cars: ");
    int totalCars = sc.nextInt();
    
    double temp1 = 0, temp2 = 0, firstPlaceTime = 0, secondPlaceTime = 0;
    int firstPlaceNumber = 0, secondPlaceNumber = 0;
    
   System.out.println("Enter car number 1 time:");
     temp1 = sc.nextDouble();
    System.out.println("Enter car number 2 time:");
    temp2 = sc.nextDouble();
    
    firstPlaceTime = Math.max(temp1, temp2);
    secondPlaceTime = Math.min(temp1, temp2);

    
    for (int i = 3; i <= totalCars; i++) {
        System.out.println("Enter car number " + i + " time:");
         double currentTime = sc.nextDouble();
        
        if (currentTime < firstPlaceTime) {
            secondPlaceTime = firstPlaceTime;
            secondPlaceNumber = firstPlaceNumber;
            firstPlaceTime = currentTime;
            firstPlaceNumber = i;
        }
        else if (currentTime < secondPlaceTime) {
            secondPlaceTime = currentTime;
            secondPlaceNumber = i;
        }
    }
    
    System.out.println("car number one is " + firstPlaceNumber +" with time of " + firstPlaceTime);
    System.out.println("car number two is " + secondPlaceNumber +" with time of " + secondPlaceTime);
}

}