From de48fa3788df79602c277fa5145ece0cccca9ae9 Mon Sep 17 00:00:00 2001
From: Pin Lin <moneycat711@gmail.com>
Date: Wed, 6 May 2020 06:46:35 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AF=A6=E4=BD=9C=E9=81=87=E5=88=B0=E5=8A=A0?=
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---
 AndroidCalculator/Calculator.swift | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/AndroidCalculator/Calculator.swift b/AndroidCalculator/Calculator.swift
index 0da621c..dd96340 100644
--- a/AndroidCalculator/Calculator.swift
+++ b/AndroidCalculator/Calculator.swift
@@ -56,6 +56,12 @@ class Calculator {
         formula.append(formula.popLast()! + text)
       }
       
+    case "+", "-", "×", "÷":
+      if ["+", "-", "×", "÷"].firstIndex(of: formula.last!) != nil {
+        formula.removeLast()
+      }
+      formula.append(text)
+      
     default:
       print(formula)
     }