我在作业上碰壁,一直在梳理网站以寻求任何有用的信息(出现空白)。我需要创建一个类,在该类中创建一个构造函数,然后再创建一个子类以扩展超类。然后,我需要使用main方法创建一个新文件来演示这两种情况。从概念上来说没问题。
我的问题是:如何使用构造函数初始化对象,但需要用户输入?
现在我得到的错误是:“类CarRental中的构造函数CarRental无法应用于给定类型;必需:String,int,String,int找到:无参数原因:实际和正式参数列表的长度不同”
请不要对“错误告诉您问题出在哪里”发表任何评论。不,它没有告诉 我 它是什么。我是这个东西的小宝贝,需要一点点握力。
我将在下面粘贴我的3个班级。因为我真是个新手,它们可能会让您痛苦不已(而且,我的课程是8周的简短课程,实际上没有时间专门用于伪代码,因此我对逻辑本身也有额外的挑战)。
我并不是在寻找任何人为我做作业,我只是在UseCarRental.java文件中寻找帮助。这是我的代码。
public class CarRental { protected String renterName; protected int zipCode; protected String carSize; protected double dailyRate; protected int rentalDays; protected double totalCost; final double ECONOMY = 29.99; final double MIDSIZE = 38.99; final double FULLSIZE = 43.50; public CarRental(String renterName, int zipCode, String carSize, int rentalDays){ totalCost = dailyRate * rentalDays; } public String getRenterName(){ return renterName; } public void setRenterName(String renter){ renterName = renter; } public int getZipCode(){ return zipCode; } public void setZipCode(int zip){ zipCode = zip; } public String getCarSize(){ return carSize; } public void setCarSize(String size){ carSize = size; } public double getDailyRate(){ return dailyRate; } public void setDailyRate(double rate){ switch (getCarSize()) { case "e": rate = ECONOMY; break; case "m": rate = MIDSIZE; break; case "f": rate = FULLSIZE; break; } } public int getRentalDays(){ return rentalDays; } public void setRentalDays(int days){ rentalDays = days; } public double getTotalCost(){ return totalCost; } public void setTotalCost(double cost){ totalCost = cost; } public void displayRental(){ System.out.println("=============================================="); System.out.println("Renter Name: " + getRenterName()); System.out.println("Renter Zip Code: " + getZipCode()); System.out.println("Car size: " + getCarSize()); System.out.println("Daily rental cost: $" + getDailyRate()); System.out.println("Number of days: " + getRentalDays()); System.out.println("Total cost: $" + getTotalCost()); } }
子类LuxuryCarRental ....
public class LuxuryCarRental extends CarRental { final double chauffeur = 200.00; final double dailyRate = 79.99; protected String chauffeurStatus; public LuxuryCarRental(String renterName, int zipCode, String carSize, int rentalDays) { super(renterName, zipCode, carSize, rentalDays); } public String getChauffeurStatus(){ return chauffeurStatus; } public void setChauffeurStatus(String driver){ chauffeurStatus = driver; } public double getChauffeurFee(){ return chauffeur; } public void setTotalLuxuryCost(){ if (chauffeurStatus=="y") setTotalCost((dailyRate * getRentalDays()) + (chauffeur * getRentalDays())); else setTotalCost(dailyRate * getRentalDays()); } @Override public void displayRental(){ System.out.println("=============================================="); System.out.println("Renter Name: " + getRenterName()); System.out.println("Renter Zip Code: " + getZipCode()); System.out.println("Car size: " + getCarSize()); System.out.println("Optional Chauffeur fee: $" + getChauffeurFee()); System.out.println("Daily rental cost: $" + getDailyRate()); System.out.println("Number of days: " + getRentalDays()); System.out.println("Total cost: $" + getTotalCost()); } }
现在是带有main方法的类:
import java.util.Scanner; public class UseRentalCar { public static void main(String[] args){ Scanner keyboard = new Scanner(System.in); CarRental rentalCar = new CarRental(); System.out.println("=========================="); System.out.println("RENTAL CAR SELECTION"); System.out.println("=========================="); System.out.println("Enter your name: "); rentalCar.setRenterName(keyboard.next()); System.out.println("Enter your zip code: "); rentalCar.setZipCode(keyboard.nextInt()); System.out.println("Enter the car size ("e=Economy, m=Midsize, f=Fullsize: "); rentalCar.setCarSize(keyboard.next()); System.out.println("Enter the number of days: "); rentalCar.setRentalDays(keyboard.nextInt()); rentalCar.displayRental(); } }
(省略了一些无关紧要的原因,主要是试图使对象实例化起作用)
谢谢你的帮助!!
在main方法中创建局部变量,例如String和int变量,然后在用用户输入填充这些变量之后,使用它们来调用构造函数。
我将发布一个一般示例,由于这是家庭作业,因此最好向您展示概念,然后让 您 使用该概念来创建代码:
public class Foo { private String name; private int value; public Foo(String name, int value) { this.name = name; this.value = value; } }
别处
import java.util.Scanner; public class Bar { public static void main(String[] args) { Scanner keyboard = new Scanner(System.in); System.out.print("Please enter name: "); String name = keyboard.nextLine(); // local variable System.out.print("Please enter value: " ); int number = keyboard.nextint(); // another local variable keyboard.nextLine(); // to handle the end of line characters // use local variables in constructor call Foo foo = new Foo(name, number); }