只有“+”“-”“*”“/”的优先级算法

public class SuanLianxi
{
       public static void main(String[] args)
       {
              //储存数值
              double[] shuzhi = new double[]{0,12,11,13,1,5,9};//任意取值验证这个优先级算法
              //储存运算符
              String[] operation = new String[]{" ","+","-","*","/"};
              //储存运算符号对应的下标
              int[] fuhao = new int[]{0,1,4,3,2,3};//解释："+"->"1"，"-"->"2"，"*"->"3"，"/"->"4"
              //12+11/13*1-5*9
              double left=0;
              double right = shuzhi[1];
              int sign = 1;
              for(int i=1;i<=5;i++)
              {
                     switch(operation[fuhao[i]])
                     {
                            case "+":
                                   left = left+sign*right;
                                   sign=1;
                                   right=shuzhi[i+1];
                                   break;
                            case "-":
                                   left = left+sign*right;
                                   sign=-1;
                                   right=shuzhi[i+1];
                                   break;
                            case "*":
                                   right=right*shuzhi[i+1];
                                   break;
                            case "/":
                                   right=right/shuzhi[i+1];
                                   break;
                     }
              }
              System.out.println(left+sign*right);//输出结果
       }
}