Update tax.sol

contracts/tax.sol

 pragma solidity ^0.4.7;
-contract tax {
+contract tax {//旧规个税计算
     function output_before(uint money)  public returns (uint) {
         uint money_before;
         uint res1;
@@ -23,7 +23,7 @@ contract tax {
       }
     return res1;
 }
-    function output_after(uint money)  public returns (uint) {
+    function output_after(uint money)  public returns (uint) {//新规个税计算
         uint money_after;
         uint res2;
         money_after=money-5000;