HELP！
内部循环（askAgain）无法正常工作。我想要它，以便当用户按下＆＃39; y＆＃39;要开始一个新的游戏，它将退出内循环并返回外部whileloop（keepPlaying）并按下＆＃39; n＆＃39;退出游戏。
如果用户既没有按下＆＃39; y＆＃39;或者＆＃39; n＆＃39;，任何其他按键，它将循环回：askAgain，直到用户做出有效选择。
该计划未按预期运作。请帮忙。
import java.util.Random;
import java.util.Scanner;
public class Game {
private int playerGuess;
private boolean keepPlaying = true;
private boolean askAgain = true;
Random randomNumber;
int generatedYear;
int generatedMonth;
int generatedDay;
/**
*
*/
public Date getRandomDate() {
randomNumber = new Random();
generatedYear = randomNumber.nextInt(600) + 1600;
generatedMonth = randomNumber.nextInt(12) + 1;
generatedDay = randomNumber.nextInt(31) + 1;
Date generatedDate = new Date (generatedYear, generatedMonth, generatedDay);
return generatedDate;
}
/**
*
*/
public void guessTheDate() {
Scanner userInput = new Scanner(System.in);
while(keepPlaying) {
int ranDateYear= getRandomDate().getYear();
System.out.println("New Game!!");
System.out.println();
System.out.print("Please guess the year. (0 - 2199): ");
while(userInput.hasNext()) {
if(userInput.hasNextInt()) {
playerGuess = userInput.nextInt();
if(playerGuess > ranDateYear) {
System.out.println("Out of bounds, too high: " + playerGuess + " (Randomized Number: " + ranDateYear+ ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else if(playerGuess < ranDateYear) {
System.out.println("Out of bounds, too low: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else{
if (playerGuess == ranDateYear) {
System.out.println("Correct! It is a match: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
System.out.print("Play again? (Y/N): ");
while (askAgain) {
while (userInput.hasNext()) {
if (userInput.hasNext()) {
String input = userInput.next();
if (input.equalsIgnoreCase("y")) {
keepPlaying = true;
} else if (input.equalsIgnoreCase("n")){
keepPlaying = false;
} else {
askAgain = true;
}
break;
}
}
}
}
}
} else {
System.out.println("Invalid input, not a number.");
System.out.print("Enter another number: ");
userInput.next();
}
}
}
System.out.println("The end. Thank you for playing!");
}
}
答案 0 :(得分：0)
在你的内部（askAgain）循环中，你永远不会将askAgain的值更改为false，导致它始终保持为真，这会导致无限循环。而是在你的内循环中尝试这个：
if(input.equalsIgnoreCase("y")) {
keepPlaying = true;
askAgain = false;
} else if(input.equalsIgnoreCase("n") {
keepPlaying = false;
askAgain = false;
} else {
askAgain = true;
答案 1 :(得分：0)
替换
while (askAgain) {
while (userInput.hasNext()) {
if (userInput.hasNext()) {
String input = userInput.next();
if (input.equalsIgnoreCase("y")) {
keepPlaying = true;
} else if (input.equalsIgnoreCase("n")){
keepPlaying = false;
} else {
askAgain = true;
}
break;
}
}
}
使用
while (true) {
String input = userInput.next();
if (input.equalsIgnoreCase("y")) {
keepPlaying = true;break;
}
else if (input.equalsIgnoreCase("n")){
keepPlaying = false;break;
}
}
它将解决当前是和否的问题，但它无法解决主要问题，您将在SO上再次提出新问题。实际上你实现代码的方式并不是很好。
<强> Now use this code for a working of your project but mind you this is also not the best way to implement the code
import java.sql.Date;
import java.util.Random;
import java.util.Scanner;
public class JavaAZ {
public static void main(String[] args) {
Game myGame = new Game();
boolean loop = false;
do {
loop = myGame.guessTheDate();
if(!loop) System.out.println("The end. Thank you for playing!");
}while(loop);
}
}
class Game{
private int playerGuess;
private boolean keepPlaying = true;
private boolean askAgain = true;
Random randomNumber;
int generatedYear;
int generatedMonth;
int generatedDay;
/**
*
*/
public Date getRandomDate() {
randomNumber = new Random();
generatedYear = randomNumber.nextInt(600) + 1600;
generatedMonth = randomNumber.nextInt(12) + 1;
generatedDay = randomNumber.nextInt(31) + 1;
Date generatedDate = new Date (generatedYear, generatedMonth, generatedDay);
return generatedDate;
}
/**
*
*/
public boolean guessTheDate() {
Scanner userInput = new Scanner(System.in);
int ranDateYear= getRandomDate().getYear();
System.out.println("New Game!!");
System.out.println();
System.out.print("Please guess the year. (0 - 2199): "+ranDateYear);
while(userInput.hasNext()) {
if(userInput.hasNextInt()) {
playerGuess = userInput.nextInt();
if(playerGuess > ranDateYear) {
System.out.println("Out of bounds, too high: " + playerGuess + " (Randomized Number: " + ranDateYear+ ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else if(playerGuess < ranDateYear) {
System.out.println("Out of bounds, too low: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else{
if (playerGuess == ranDateYear) {
System.out.println("Correct! It is a match: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
while (true) {
System.out.print("Play again? (Y/N): ");
String input = userInput.next();
if (input.equalsIgnoreCase("y")) {
return true;
} else if (input.equalsIgnoreCase("n")){
return false;
}
}
}
}
} else {
System.out.println("Invalid input, not a number.");
System.out.print("Enter another number: ");
userInput.next();
}
}
return false;
}
}
这是以你的方式运作你的代码
import java.sql.Date;
import java.util.Random;
import java.util.Scanner;
public class Game {
private int playerGuess;
private boolean keepPlaying = true;
private boolean askAgain = true;
Random randomNumber;
int generatedYear;
int generatedMonth;
int generatedDay;
public static void main(String[] args) {
Game g = new Game();
g.guessTheDate();
}
/**
*
*/
public Date getRandomDate() {
randomNumber = new Random();
generatedYear = randomNumber.nextInt(600) + 1600;
generatedMonth = randomNumber.nextInt(12) + 1;
generatedDay = randomNumber.nextInt(31) + 1;
Date generatedDate = new Date (generatedYear, generatedMonth, generatedDay);
return generatedDate;
}
/**
*
*/
public void guessTheDate() {
Scanner userInput = new Scanner(System.in);
while(keepPlaying) {
int ranDateYear= getRandomDate().getYear();
System.out.println("New Game!!");
System.out.println();
System.out.print("Please guess the year. (0 - 2199): "+ranDateYear);
while(userInput.hasNext()) {
if(userInput.hasNextInt()) {
playerGuess = userInput.nextInt();
if(playerGuess > ranDateYear) {
System.out.println("Out of bounds, too high: " + playerGuess + " (Randomized Number: " + ranDateYear+ ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else if(playerGuess < ranDateYear) {
System.out.println("Out of bounds, too low: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else{
if (playerGuess == ranDateYear) {
System.out.println("Correct! It is a match: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
System.out.print("Play again? (Y/N): ");
while (true) {
String input = userInput.next();
if (input.equalsIgnoreCase("y")) {
keepPlaying = true;break;
}
else if (input.equalsIgnoreCase("n")){
keepPlaying = false;break;
}
}
break;
}
}
} else {
System.out.println("Invalid input, not a number.");
System.out.print("Enter another number: ");
userInput.next();
}
}
}
System.out.println("The end. Thank you for playing!");
}
}
答案 2 :(得分：0)
if (userInput.hasNext()) {
String input = userInput.next();
if (input.equalsIgnoreCase("y")) {
keepPlaying = true;
askAgain = false;
} else if (input.equalsIgnoreCase("n")){
keepPlaying = false;
askAgain = false;
} else {
askAgain = true;
}
break;
}
请参阅此http://api.dataatwork.org/v1/spec/
修改
将 while（userInput.hasNext（））{替换为告诉用户输入的变量，因此在askAgain循环中，此变量将变为false。
试试这个：
while(enteringInput) {
try{
playerGuess = userInput.nextInt();
if(playerGuess > ranDateYear) {
System.out.println("Out of bounds, too high: " + playerGuess + " (Randomized Number: " + ranDateYear+ ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else if(playerGuess < ranDateYear) {
System.out.println("Out of bounds, too low: " + playerGuess + " (Randomized Number: " + ranDateYear + ")");
System.out.println();
System.out.println("Try again!");
System.out.print("Please guess the year (0 - 2199): ");
}else{
if (playerGuess == ranDateYear) {
System.out.println("Correct! It is a match: " + playerGuess + " (Randomized Number: " + ranDateYear +")");
System.out.println();
System.out.print("Play again? (Y/N): ");
while (askAgain) {
System.out.print(askAgain);
while (userInput.hasNext()) {
String input = userInput.nextLine();
if (input.equalsIgnoreCase("y")) {
keepPlaying = true;
askAgain = false;
} else if (input.equalsIgnoreCase("n")){
keepPlaying = false;
askAgain = false;
enteringInput = false;
} else {
askAgain = true;
}
break;
}
}
}
}
}catch(Exception e){
System.out.println("Invalid input");
userInput.nextLine();
}
}