Question

我正在练习制作自己的课程，最终我想建立一个包含这3辆车的车队并计算平均MPG。我很难把车开进车棚。我认为我的问题是实例变量，但我无法弄清楚该怎么做。

import java.util.Scanner;

class CarFleet {

    Car car1;
    Car car2;
    Car car3;

    CarFleet(first, second, third) {
        car1 = first;
        car2 = second;
        car3 = third;
    }
}

class Car {

    double startMiles;
    double endMiles;
    double gallons;

    Car(double initialMiles, double endingMiles, double tankGals) {
        startMiles = initialMiles;
        endMiles = endingMiles;
        gallons = tankGals;
    }

    public double calculateMPG() {
        return (endMiles - startMiles) / gallons;
    }
}

class MPG {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        //System.out.println("Initial miles for trip: ");
        //double initMiles = scan.nextDouble();
        //System.out.println("End miles for trip: ");
        //double endMiles = scan.nextDouble();
        //System.out.println("Gallons used for trip: ");
        //double gals = scan.nextDouble();

        Car Lambo = new Car(0, 335, 9.5);
        String car1 = "Lambo";
        System.out.println("Your " + car1 + " goes " + Lambo.calculateMPG() + "        MPG");

        Car Honda = new Car(0, 24, 2);
        String car2 = "Honda";
        System.out.println("Your " + car2 + " goes " + Honda.calculateMPG() + " MPG");

        Car Eclipse = new Car(0, 48, 3);
        String car3 = "Eclipse";
        System.out.println("Your " + car3 + " goes " + Eclipse.calculateMPG() + " MPG");

        CarFleet coolCars = new CarFleet(Lambo, Honda, Eclipse);
    }
}

Answer 1

像这样

CarFleet(Car first, Car second,Car third) {
 this.car1 = first;
 this.car2 = second;
 this.car3 = third;
}

Answer 2

问题出在这条线上。

 CarFleet(first, second, third){

基本上，您定义了一个构造函数，但是没有给编译器提供关于 Type first，second和third是什么的信息。

解决方案是使用

 CarFleet(Car first, Car second, Car third) {

现在指定每个变量的 Type 。

如何在构造函数中使用我的Car对象引用？

2 个答案: