Infix expression to postfix expression

Rule: For operators of the same level, the priority of the left parenthesis in the stack is higher than that of the outside of the stack. 
The left parenthesis outside the stack has the highest    
priority 
and is pushed into the stack. The left parentheses in the stack have the same priority 




// The application of the station 
/* The infix expression is converted into a postfix expression
             Infix expression strMid: 2+3*5-4*(5-3)
             Postfix expression strMid: 235*+453-*-       
 *
 *
 *
 *
 */
package com.tulun;
import java.util.Arrays;


public class TestMl3 {
    class Constant {

        /**
         * means addition
         / 
        _  _  _  _ _   _ _ 
        _  _  _  _ _    _ _ 
        _  _  _  _   _ _ _ 
        _  _  _  _ _   _ / In-stack division 
        public  static  final  int OPERATORS_PRIO_LEFT_BRAK_IN = 10;   // In-stack left bracket

        public  static  final  int OPERATORS_PRIO_PLUS_OUT = 5 ; // Addition outside the stack 
        public  static  final  int OPERATORS_PRIO_SUB_OUT = 5;    // Subtraction outside the stack 
        public  static  final  int OPERATORS_PRIO_MULTY_OUT = 3; // Multiplication outside the stack 
        public  static  final  int OPERATORS_PRIO_DIV_OUT = 3;    // Stack External division method 
        public  static  final  int OPERATORS_PRIO_LEFT_BRAK_OUT = 1;   // Left parenthesis outside the stack 
        public  static  final  intOPERATORS_PRIO_RIGHT_BRAK_OUT = 10;   // Right bracket outside the stack 
        public  static  final  int OPERATORS_PRIO_ERROR = -1 ;
        

    }
    public static int getPrio(char opera,boolean instack){
        
        int prio = Constant.OPERATORS_PRIO_ERROR;
        if(instack){
            switch(opera) {
            case '+':
                prio = Constant.OPERATORS_PRIO_PLUS_IN;
                break;
            case '-':
                prio = Constant.OPERATORS_PRIO_SUB_IN;
                break;
            case '*':
                prio = Constant.OPERATORS_PRIO_MULTY_IN;
                break;
            case '/':
                prio = Constant.OPERATORS_PRIO_DIV_IN;
                break;
            case '(':
                prio = Constant.OPERATORS_PRIO_LEFT_BRAK_IN;
                break;
            default:
                prio = Constant.OPERATORS_PRIO_ERROR;
                break;
            }
        }else{
        
            switch(opera){
        
            case '+':
                prio = Constant.OPERATORS_PRIO_PLUS_OUT;
                break;
            case '-':
                prio = Constant.OPERATORS_PRIO_SUB_OUT;
                break;
            case '*':
                prio = Constant.OPERATORS_PRIO_MULTY_OUT;
                break;
            case '/':
                prio = Constant.OPERATORS_PRIO_DIV_OUT;
                break;
            case '(':
                prio = Constant.OPERATORS_PRIO_LEFT_BRAK_OUT;
                break;
            case ')':
                prio = Constant.OPERATORS_PRIO_RIGHT_BRAK_OUT;
                break;
            default:
                prio = Constant.OPERATORS_PRIO_ERROR;
                break;
            }
        }
        return prio;
    }
    
       public static void strMidToLast(String strMid,char[]strLast){
       //模拟栈
       char[]stack = new char[strMid.length()];
       int top=0;
       
       int len= strMid.length();
        int i=0; // count is used to count the subscript of strMid 
       int j=0; // count is used to indicate the subscript of strMid 
       int prioIn; // the priority in the stack 
       int prioOut; // Priority outside the stack
        // traverse strMid 
       while (i!= len){
            if (Character.isDigit(strMid.charAt(i))){
               strLast[j]=strMid.charAt(i);
               j++;
               i++;
           } else {
                if (top==0){ // stack is empty 
                   stack[top]= strMid.charAt(i);
                   top++;
                   i++;
               }else{
                   prioIn=getPrio(stack[top-1],true);
                   prioOut=getPrio(strMid.charAt(i),false);
               
                   if(prioIn<prioOut){
                   strLast[j++]=stack[--top];
                   }
                   else if(prioIn==prioOut){
                      top--;
                      i++;
                   }else{
                       stack[top++]=strMid.charAt(i);
                       i++;
                   
                   }
               }
           
           }
           }
       while(top>0){
               strLast[j++]=stack[--top];
       }
       }
       public static void show(char[]strLast){
           for(int i=0;i<strLast.length;i++){
               System.out.println(strLast[i]);
           }
           System.out.println();
       }
       public static void main(String[] args) {
         // TODO Auto-generated method stub
         String strMid="2+3*5-4*(5-3)";
         char[]strLast=new char[strMid.length()];
         strMidToLast(strMid,strLast);
         System.out.println(Arrays.toString(strLast));
       }

}