只有“+”“-”“*”“/”的优先级算法

 1 public class SuanLianxi
 2 {
 3        public static void main(String[] args)
 4        {
 5               //储存数值
 6               double[] shuzhi = new double[]{0,12,11,13,1,5,9};//任意取值验证这个优先级算法
 7               //储存运算符
 8               String[] operation = new String[]{" ","+","-","*","/"};
 9               //储存运算符号对应的下标
10               int[] fuhao = new int[]{0,1,4,3,2,3};//解释:"+"->"1","-"->"2","*"->"3","/"->"4"
11               //12+11/13*1-5*9
12               double left=0;
13               double right = shuzhi[1];
14               int sign = 1;
15               for(int i=1;i<=5;i++)
16               {
17                      switch(operation[fuhao[i]])
18                      {
19                             case "+":
20                                    left = left+sign*right;
21                                    sign=1;
22                                    right=shuzhi[i+1];
23                                    break;
24                             case "-":
25                                    left = left+sign*right;
26                                    sign=-1;
27                                    right=shuzhi[i+1];
28                                    break;
29                             case "*":
30                                    right=right*shuzhi[i+1];
31                                    break;
32                             case "/":
33                                    right=right/shuzhi[i+1];
34                                    break;
35                      }
36               }
37               System.out.println(left+sign*right);//输出结果
38        }
39 }

 
posted @ 2015-08-13 17:50  何杨  阅读(408)  评论(0编辑  收藏  举报