“线程中的异常”;“主要”;java.lang.IllegalArgumentException:n必须为正
以下是我的错误消息:“线程中的异常”;“主要”;java.lang.IllegalArgumentException:n必须为正,java,Java,以下是我的错误消息: Exception in thread "main" java.lang.IllegalArgumentException: n must be positive at java.util.Random.nextInt(Random.java:265) at Game.generateSecretNumber(Game.java:44) at Game.start(Game.java:32) at Game.main(Game.java:18
Exception in thread "main" java.lang.IllegalArgumentException: n must be positive
at java.util.Random.nextInt(Random.java:265)
at Game.generateSecretNumber(Game.java:44)
at Game.start(Game.java:32)
at Game.main(Game.java:18
我的代码是:
import java.util.Random;
import java.util.Scanner;
public class Game {
private final int LOWER_BOUND = 1;
private int secretNumber;
private int top;
private static enum Response {YES, NO}
private Random random;
private Scanner scanner;
public static void main(String[] args) {
Game GuessingGame = new Game();
GuessingGame.start();
}
public Game() {
random = new Random( );
scanner = new Scanner(System.in);
}
public void start() {
Response answer;
answer = Response.YES;
while (answer == Response.YES) {
generateSecretNumber();
playGame();
answer = prompt("");
}
System.out.println("Bye!");
}
private void generateSecretNumber() {
secretNumber = random.nextInt(top) + 1;
System.out.println("You are going to guess a number between 1 and what number? ");
top = scanner.nextInt();
System.out.println("Type a number between 1 and: " + top);
}
private void playGame() {
int guessCount = 0;
int guess;
do {
guess = getNextGuess();
guessCount++;
if (guess < secretNumber) {
System.out.println("Too low. Try again:");
}
else if
(guess > secretNumber) {
System.out.println("Too high. Try again:");
}
}
while ( guess != secretNumber );
if ( guess == secretNumber ) {
System.out.println("Right! It took you " + guessCount + " tries");
}
else {
System.out.println("game over");
}
}
private Response prompt(String question) {
String input;
Response response = Response.NO;
System.out.print(question + "Would you like to play again? ");
input = scanner.next();
if (input.equals("Y") || input.equals("y")) {
response = Response.YES;
}
return response;
}
private int getNextGuess() {
int input;
while(true) {
System.out.print(" ");
input = scanner.nextInt();
if (LOWER_BOUND <= input && input <= top) {
return input;
}
System.out.println("Invalid input: " + "must be between " + LOWER_BOUND + " and" + top);
}
}
}
import java.util.Random;
导入java.util.Scanner;
公开课游戏{
私有最终整数下界=1;
私密密文编号;
私人int top;
私有静态枚举响应{YES,NO}
私有随机;
私人扫描仪;
公共静态void main(字符串[]args){
游戏猜测游戏=新游戏();
猜游戏。开始();
}
公共游戏(){
random=新的random();
扫描仪=新扫描仪(System.in);
}
公开作废开始(){
回答;
回答=回答。是;
while(answer==Response.YES){
generateScretNumber();
游戏();
回答=提示(“”);
}
System.out.println(“再见!”);
}
私有void generateScretnumber(){
secretNumber=random.nextInt(顶部)+1;
System.out.println(“您要猜一个介于1和什么数字之间的数字?”);
top=scanner.nextInt();
System.out.println(“键入一个介于1和:“+top”之间的数字);
}
私人游戏{
int猜测计数=0;
智力猜测;
做{
guess=getNextGuess();
猜数++;
如果(猜测秘密数字){
System.out.println(“太高,请重试:”);
}
}
while(猜测!=秘密数字);
如果(猜测==秘密数字){
System.out.println(“对!你用了”+猜数+“尝试”);
}
否则{
System.out.println(“游戏结束”);
}
}
私人响应提示(字符串问题){
字符串输入;
Response=Response.NO;
System.out.print(问题+“您想再次播放吗?”);
输入=scanner.next();
if(input.equals(“Y”)| input.equals(“Y”)){
response=response.YES;
}
返回响应;
}
private int getNextGuess(){
int输入;
while(true){
系统输出打印(“”);
输入=scanner.nextInt();
如果第一次调用top
时的(下限为零,则random.nextInt(top)
抛出异常。此方法只能用正数调用。使用
secretNumber=random.nextInt(顶部)+1;
在top
被指定一个有意义的值之前(除了默认的0
值;由于它需要一个正值,所以随机抛出一个异常)。当您调用时:random。第44行的nextInt(top)
传递0(因为这是“top”变量的值)
您必须传递大于0的内容
这就是“n必须是正的”的意思。在你的帖子中没有问题。@thejh:0
是未初始化时的默认值,是的(编辑了一点以进一步澄清)。private int top=1;我将初始值指定为1。现在似乎工作正常。