我正在嘗試實作一個 printAnimals() 方法，該方法為狗列印 ArrayList 或為猴子列印 ArrayList，或列印所有訓練狀態為“服務中”且未保留的動物，具體取決于您在選單中輸入的輸入. 我正在嘗試為包含 if 陳述句的兩個 ArrayList 正確撰寫 for 回圈，因此它將列印 ArrayList 中滿足條件的任何專案，即它們的 trainingStatus 等于“in service”并且保留 = false。
我目前在 printAnimals() 方法下有一個錯誤，顯示“方法 dogList(int) 未定義為型別驅動程式”，另一條錯誤訊息顯示“方法monkeyList(int) 未定義為型別驅動程式”。您知道如何正確鍵入回圈遍歷 ArrayList 并具有 if 陳述句的 for 回圈嗎？這是我到目前為止的代碼：
import java.util.ArrayList;
import java.util.Scanner;
public class Driver {
private static ArrayList<Dog> dogList = new ArrayList<Dog>();
private static ArrayList<Monkey> monkeyList = new ArrayList<Monkey>();
// Instance variables (if needed)
public static void main(String[] args) {
initializeDogList();
initializeMonkeyList();
// Creates a scanner class object
Scanner input = new Scanner(System.in);
char option;
// Displays the menu in loop until the user enters the exit option
do
{
displayMenu();
option=input.next().charAt(0);
// If user input is 1, intakeNewDog method is called
if(option=='1') {
intakeNewDog(input);
}
// If the option is 2, the intakeNewMonkey method is called
else if(option=='2') {
intakeNewMonkey(input);
}
// If the option is 3, the reserveAnimal method is called
else if(option=='3') {
reserveAnimal(input);
}
// If the option is 4, the printAnimals method is called to print dog list
else if(option=='4') {
printAnimals(option);
}
// If the option is 5, the printAnimals method is called to print monkey list
else if(option=='5') {
printAnimals(option);
}
// If the option is 6, the printAnimals method is called to print all available
animals
else if(option=='6') {
printAnimals(option);
}
// If the option is q, exit message prints and application stops running
else if(option=='q') {
System.out.print("You have exited the application.");
break;
}
else {
System.out.print("You have entered an invalid input.");
}
}while (option != 'q');
}
// This method prints the menu options
public static void displayMenu() {
System.out.println("\n\n");
System.out.println("\t\t\t\tRescue Animal System Menu");
System.out.println("[1] Intake a new dog");
System.out.println("[2] Intake a new monkey");
System.out.println("[3] Reserve an animal");
System.out.println("[4] Print a list of all dogs");
System.out.println("[5] Print a list of all monkeys");
System.out.println("[6] Print a list of all animals that are not reserved");
System.out.println("[q] Quit application");
System.out.println();
System.out.println("Enter a menu selection");
}
// Adds dogs to a list for testing
public static void initializeDogList() {
Dog dog1 = new Dog("Spot", "German Shepherd", "male", "1", "25.6", "05-12-2019", "United
States", "intake", false, "United States");
Dog dog2 = new Dog("Rex", "Great Dane", "male", "3", "35.2", "02-03-2020", "United
States", "Phase I", false, "United States");
Dog dog3 = new Dog("Bella", "Chihuahua", "female", "4", "25.6", "12-12-2019", "Canada",
"in service", true, "Canada");
dogList.add(dog1);
dogList.add(dog2);
dogList.add(dog3);
}
// Adds monkeys to a list for testing
//Optional for testing
public static void initializeMonkeyList() {
Monkey monkey1 = new Monkey("Albert", "male", "8", "9.5", "06-12-2019", "Costa Rica", "in
service", false, "United States", "17.6", "18.4", "18.1", "Capuchin");
Monkey monkey2 = new Monkey("Ada", "female", "6", "1.2", "04-18-2020", "Brazil", "Phase
4", true, "Canada", "13.2", "10.1", "9.9", "Tamarin");
Monkey monkey3 = new Monkey("Galileo", "male", "7", "7.8", "11-22-2019", "Congo", "Phase
3", false, "United States", "26.2", "20.3", "21.2", "Guenon");
monkeyList.add(monkey1);
monkeyList.add(monkey2);
monkeyList.add(monkey3);
}
// Complete the intakeNewDog method
// The input validation to check that the dog is not already in the list
// is done for you
public static void intakeNewDog(Scanner scanner) {
scanner.nextLine();
System.out.println("What is the dog's name?");
String name = scanner.nextLine();
for(Dog dog: dogList) {
if(dog.getName().equalsIgnoreCase(name)) {
System.out.println("\n\nThis dog is already in our system\n\n");
return; //returns to menu
}
}
// Add the code to instantiate a new dog and add it to the appropriate list
System.out.println("What is the dog's breed?");
String breed = scanner.nextLine();
System.out.println("What is the dog's gender?");
String gender = scanner.nextLine();
System.out.println("What is the dog's age?");
String age = scanner.nextLine();
System.out.println("What is the dog's weight?");
String weight = scanner.nextLine();
System.out.println("When was this dog acquired?");
String acquisitionDate = scanner.nextLine();
System.out.println("Which country was this dog acquired?");
String acquisitionCountry = scanner.nextLine();
System.out.println("What is the dog's training status?");
String trainingStatus = scanner.nextLine();
System.out.println("Is this dog reserved?");
boolean reserved = scanner.nextBoolean();
scanner.nextLine();
System.out.println("Which country is the dog in service?");
String inServiceCountry = scanner.nextLine();
Dog dog4 = new Dog(name, breed, gender, age, weight, acquisitionDate, acquisitionCountry,
trainingStatus, reserved, inServiceCountry);
dogList.add(dog4);
System.out.println("Your entry has been added to the dog list.");
}
// Complete intakeNewMonkey
//Instantiate and add the new monkey to the appropriate list
// For the project submission you must also validate the input
// to make sure the monkey doesn't already exist and the species type is allowed
public static void intakeNewMonkey(Scanner scanner) {
scanner.nextLine();
System.out.println("What is the monkey's name?");
String name = scanner.nextLine();
for(Monkey monkey: monkeyList) {
if(monkey.getName().equalsIgnoreCase(name)) {
System.out.println("\n\nThis monkey is already in our system\n\n");
return; //returns to menu
}
}
System.out.println("What is the monkey's gender?");
String gender = scanner.nextLine();
System.out.println("What is the monkey's age?");
String age = scanner.nextLine();
System.out.println("What is the monkey's weight?");
String weight = scanner.nextLine();
System.out.println("When was this monkey acquired?");
String acquisitionDate = scanner.nextLine();
System.out.println("Which country was this monkey acquired?");
String acquisitionCountry = scanner.nextLine();
System.out.println("What is the monkey's training status?");
String trainingStatus = scanner.nextLine();
System.out.println("Is this monkey reserved?");
boolean reserved = scanner.nextBoolean();
scanner.nextLine();
System.out.println("Which country is the monkey in service?");
String inServiceCountry = scanner.nextLine();
System.out.println("How long is the monkey's tail?");
String tailLength = scanner.nextLine();
System.out.println("What is the monkey's height?");
String height = scanner.nextLine();
System.out.println("What is the monkey's body length?");
String bodyLength = scanner.nextLine();
System.out.println("What species is the monkey?");
String species = scanner.nextLine();
Monkey monkey4 = new Monkey(name, gender, age, weight, acquisitionDate,
acquisitionCountry, trainingStatus, reserved, inServiceCountry, tailLength, height,
bodyLength, species);
monkeyList.add(monkey4);
System.out.print("Your entry has been added to the monkey list.");
}
// Complete reserveAnimal
// You will need to find the animal by animal type and in service country
public static void reserveAnimal(Scanner scanner) {
scanner.nextLine();
System.out.println("Enter animal type: ");
String animalType = scanner.nextLine();
if (animalType.equalsIgnoreCase("Monkey")) {
System.out.println("Enter the monkey's country of acquisiton: ");
String country = scanner.nextLine();
for(Monkey obj: monkeyList) {
if(obj.getAcquisitionLocation().equalsIgnoreCase(country)) {
obj.setReserved(true);
System.out.println("This monkey is now reserved.");
return;
}
}
System.out.println("The monkey entered is not in the list");
}
else if (animalType.equalsIgnoreCase("Dog")) {
System.out.println("Enter the dog's country of acquisition: ");
String country = scanner.nextLine();
for(Dog obj: dogList){
if(obj.getAcquisitionLocation().equalsIgnoreCase(country)){
obj.setReserved(true);
System.out.println("This dog is now reserved.");
return;
}
}
System.out.println("The dog entered is not in the list");
} else {
System.out.println("Type not found");
}
}
public static void printAnimals(char option) {
if (option == '4') {
System.out.println(dogList);
}
else if (option == '5') {
System.out.println(monkeyList);
}
else if (option == '6') {
// Iterates through dogs
for (int i = 0; i < dogList.size(); i ) {
if (dogList(i).getTrainingStatus.equals("in service") &&
dogList(i).getReserved()==false) {
// Prints dogs that are in service and available
System.out.println(dogList.get(i));
}
}
// Iterates through monkeys
for (int i = 0; i < monkeyList.size(); i ) {
if (monkeyList(i).getTrainingStatus().equalsIgnoreCase("in service") &&
monkeyList(i).getReserved()==false) {
// Prints monkeys that are in service and available
System.out.println(monkeyList.get(i));
}
}
}
}
}
uj5u.com熱心網友回復：
在這里找我一個錯誤：
if (dogList(i).getTrainingStatus.equals("in service") &&
dogList(i).getReserved()==false) {
這應該是：
if (dogList.get(i).getTrainingStatus.equals("in service") &&
dogList.get(i).getReserved()==false) {
嘗試一下，讓我知道現在是否有效。
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