令牌“;”上的语法错误，{在随机字符串创建者中此令牌之后

由 mest发布于 2020-04-09 07:29:28

我正在编写代码以使用字母a，b和c生成随机的3个字母字符串。我在创建随机变量的行（Random rand = new Random（）;）行后收到错误消息“令牌“;”上的语法错误，{预期在此令牌之后”。我不知道为什么在我觉得很好时会收到此错误。

我还收到错误消息：语法错误，在程序中的最后一个括号之后插入“}”以完成ClassBody。我几乎认为我所有的右括号都匹配，所以我不知道此错误来自何处。请帮忙！！

 import java.util.*;


 public class Orders {

String alphabet = "abc";
ArrayList<String> list = new ArrayList<String>();
int n = alphabet.length();

Random rand = new Random();
for (int i = 0; i < 10000; i++){
    char a = alphabet.charAt(rand.nextInt(n));
    char b = alphabet.charAt(rand.nextInt(n));
    char c = alphabet.charAt(rand.nextInt(n));

    String s = Character.toString(a) + Character.toString(b) + Character.toString(c); 

    if(list.indexOf(s) == -1){
        list.add(s);
    }
}
 system.out.println(arrayList);
}

甜小妞

2020-04-09 07:29:28

在Java中，您不能直接在类中编写可执行语句。您需要在一种方法中移动代码。在方法/块之外仅允许声明变量。仅出于测试目的，将所有内容移至主要方法。尝试这个：

  public class Orders {

        public static void main(String argsp[]) {
            String alphabet = "abc";
            ArrayList<String> list = new ArrayList<String>();
            int n = alphabet.length();

            Random rand = new Random();
            for (int i = 0; i < 10000; i++){
               char a = alphabet.charAt(rand.nextInt(n));
               char b = alphabet.charAt(rand.nextInt(n));
               char c = alphabet.charAt(rand.nextInt(n));

               String s = Character.toString(a) + Character.toString(b) + Character.toString(c); 

               if(list.indexOf(s) == -1){
                   list.add(s);
               }
            }
            System.out.println(list);
        }

}

Note: system.out.println(arrayList); will throw an error because there is no varaible called arrayList, i think it should be replaced with variable list. Also system should be System.

涂鸦

2020-04-09 07:29:28

在Java中，您不能简单地将循环和其他操作编码为类定义的一部分，而是作为类内的方法/构造函数/块定义

for (int i = 0; i < 10000; i++){
    char a = alphabet.charAt(rand.nextInt(n));
    char b = alphabet.charAt(rand.nextInt(n));
    char c = alphabet.charAt(rand.nextInt(n));

    String s = Character.toString(a) + Character.toString(b) + Character.toString(c); 

    if(list.indexOf(s) == -1){
        list.add(s);
    }
}
 system.out.println(arrayList);

因此，此代码应位于method / constructor / block中。例如方法

public void printList(){
 for (int i = 0; i < 10000; i++){
        char a = alphabet.charAt(rand.nextInt(n));
        char b = alphabet.charAt(rand.nextInt(n));
        char c = alphabet.charAt(rand.nextInt(n));

        String s = Character.toString(a) + Character.toString(b) + Character.toString(c); 

        if(list.indexOf(s) == -1){
            list.add(s);
        }
    }
     system.out.println(arrayList);  
}

Please refer this link for more details.

我爱RMB

2020-04-09 07:29:28

您只需要在main函数中编写代码。您只是错过了主要功能。

您的密码

import java.util.*;
 public class Orders {//Include main function

 String alphabet = "abc";
ArrayList<String> list = new ArrayList<String>();
int n = alphabet.length();

Random rand = new Random();
for (int i = 0; i < 10000; i++){
    char a = alphabet.charAt(rand.nextInt(n));
    char b = alphabet.charAt(rand.nextInt(n));
    char c = alphabet.charAt(rand.nextInt(n));

    String s = Character.toString(a) + Character.toString(b) + Character.toString(c); 

    if(list.indexOf(s) == -1){
        list.add(s);
    }
}
 system.out.println(arrayList);
}

正确的代码

package testprob;
import java.util.*;
public class testprob {
public static void main(String arrg[]) {//you need to add main function 
     String alphabet = "abc";
     ArrayList<String> list = new ArrayList<String>();
     int n = alphabet.length();

     Random rand = new Random();
     for (int i = 0; i < 10000; i++){
         char a = alphabet.charAt(rand.nextInt(n));
         char b = alphabet.charAt(rand.nextInt(n));
         char c = alphabet.charAt(rand.nextInt(n));

         String s = Character.toString(a) + Character.toString(b) + Character.toString(c); 

         if(list.indexOf(s) == -1){
             list.add(s);
         }
     }
      System.out.println(list);

}

}

isunt

2020-04-09 07:29:28

当我按如下方式进行编码时，出现错误“无效令牌'manage（）...”。那是当我直接将代码编写到类中时。

//之前

public class test{ WebDriver driver=new FirefoxDriver(); driver.manage().timeouts().pageLoadTimeout(30, TimeUnit.SECONDS); driver.get("http://http://www.extjs-tutorial.com/live-examples/extjs4/CRUD-in-Form-model/default.htm"); }'

在将代码移至方法后，它开始工作了

//后

 public class test{
    public void setup(){
    WebDriver driver=new FirefoxDriver();
    driver.manage().timeouts().pageLoadTimeout(30, TimeUnit.SECONDS);
    driver.get("http://http://www.extjs-tutorial.com/live-examples/extjs4/CRUD-in-Form-model/default.htm");
    }}

夜伴歌笙

2020-04-09 07:29:28

在该代码中出现语法错误的原因是，您有一个额外的括号。到上面的错误代码！

mest

这家伙很懒，什么都没留下

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