令牌上的语法错误 [英] Syntax error on tokens

问题描述

我收到一个我不明白的错误：

此行上的多个标记
- 令牌上的语法错误，错放
construct（s）
- 令牌上的语法错误，删除这些令牌

以下是我的类代码，错误发生在第8行（标记）：

  import java.util。*; 
 
 public class stringCalculator {
 String operator_array [] = {+， - ，/，*，（，）}; 
队列<整数> outputQueue = new LinkedList< Integer>（）; 
堆栈< Object> operatorStack = new Stack< Object>（）; 
 Hashtable< String，Integer> precendece = new Hashtable< String，Integer>（）; 
 precedence.put（+，2）; < ===========这是发生错误的地方
 
 public void printTokenList（String [] expression，int length）
 {
 for int i = 0; i< length; i ++）{
 System.out.println（expression [i]）; 
} 
} 
 
 public void checkInput（String [] expression，int length）
 {
 System.out.println（expression）; （int i = 0; i< length; i ++）{
 if（checkIfNumber（expression [i]））{
 int new_expression = Integer.parseInt（expression [i ]）; 
 outputQueue.add（new_expression）; 
} 
 else if（expression [i] .equals（+）|| expression [i] .equals（ - ）|| expression [i] .equals（/）| |表达式[i] .equals（*））{
 for（int j = 0; j< 6; j ++）{
 if（expression [i] .equals（operator_array [j] ））{
 operatorStack.push（expression [i]）; 
} 
} 
} 
} 
} 
 
 public static boolean checkIfNumber（String expression）
 {
尝试
 {
 double number = Double.parseDouble（expression）; 
} 
 catch（NumberFormatException nfe）
 {
 return false; 
} 
返回true; 
} 
 
 public void checkPrecedence（）
 {
 
} 
} 
  pre> 
 
解决方案
语句 precedence.put（+，2）; 必须在方法或块内。 
 
 
 
例如，您可以将其放在构造函数中
  public stringCalculator（）{
 precedence.put（+，2）; 
} 
  
与您所遇到的问题无关，课程需要以大写字母开头，根据 Java命名约定 
 
I am getting an error which i don't understand:

Multiple markers at this line
    - Syntax error on token(s), misplaced 
     construct(s)
    - Syntax error on tokens, delete these tokens

The following is my code for the class, error occurs in line 8 (marked):
import java.util.*;

public class stringCalculator {
    String operator_array[] = {"+", "-", "/", "*", "(", ")"};
    Queue<Integer> outputQueue = new LinkedList<Integer>();
    Stack <Object> operatorStack = new Stack<Object>();
    Hashtable<String, Integer> precendece = new Hashtable<String, Integer>();
    precedence.put("+", 2); <=========== This is where the error occurs

    public void printTokenList(String [] expression, int length)
    {
        for(int i = 0; i < length; i++){
            System.out.println(expression[i]);
        }
    }

    public void checkInput(String [] expression, int length)
    {
        System.out.println(expression);
        for(int i = 0; i < length; i ++){
                if(checkIfNumber(expression[i])){
                int new_expression = Integer.parseInt(expression[i]);
                outputQueue.add(new_expression);
            }
            else if(expression[i].equals("+") || expression[i].equals("-") || expression[i].equals("/") || expression[i].equals("*")){
                for(int j = 0; j < 6; j++){
                    if(expression[i].equals(operator_array[j])){
                    operatorStack.push(expression[i]);
                    }
                }
            }
        }
    }

    public static boolean checkIfNumber(String expression)  
    {  
      try  
      {  
          double number = Double.parseDouble(expression);  
      }  
      catch(NumberFormatException nfe)  
      {  
        return false;
      }  
      return true;  
    }

    public void checkPrecedence()
    {

    }
}

解决方案
The statement precedence.put("+", 2); has to be within a method or a block. 

For example, you can place it within the constructor
public stringCalculator() {
    precedence.put("+", 2);
}
Not related to the problem you have, classes need to start with a capital letter, according to the Java Naming Conventions

                        
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