[java]输入一个算术表达式输出结果

动手有益。

输入一个表达式，没有括号，数字小于0-9之间，输出计算结果，所有的中间结果化为整形。
例如:  输入：3+8×2/9-2  
输出：2  

     /**
     * input a calculate string, calcuate the value
     * the number between 0-9
     * round the middle vlaue to int
     * */
    public static void main(String[] args) {    

        //8*6+2-6/3*6+2 
        String cal;//=new Scanner(System.in).nextLine();
        cal="8*6+2-6/3*6+2";
        String[] car=new String[cal.length()];
        for (int i = 0; i < car.length; i++) {
            car[i]=""+cal.charAt(i);
        }
        
        System.err.println(car);
        
        //do * and /
        for (int i = 0; i < car.length; i++) {
            if(car[i].equals("*"))
            {
                car[i+1]= ""+(Integer.parseInt(car[i-1]) * Integer.parseInt(car[i+1]));
                car[i-1]="";
                car[i]="";
                
            }else if(car[i].equals("/"))
            {
                car[i+1]= ""+(Integer)(Integer.parseInt(car[i-1]) / Integer.parseInt(car[i+1]));
                car[i-1]="";
                car[i]="";
            }
            else {
                continue;
            }
        }
        
        //do + and -
        int index=0;
        for (int i = 0; i < car.length; i++) {
            index=i;            
            if(car[i].equals("+"))
            {
                while(car[++index].equals("")){}                    
                car[index]= ""+(Integer.parseInt(car[i-1]) + Integer.parseInt(car[index]));
                car[i-1]="";
                car[i]="";
                
            }else if(car[i].equals("-"))
            {
                while(car[++index].equals("")){}                    
                car[index]= ""+(Integer.parseInt(car[i-1]) - Integer.parseInt(car[index]));
                car[i-1]="";
                car[i]="";
            }
            else {
                continue;
            }
        }
        
        System.err.println(cal+" = "+car[car.length-1]);
        
    }