diff --git a/calc.py b/calc.py
index e15ad9f7f511d856d657f689f4ebbcc90c53c34a..ffff18cc923fdfec663adb198a1482137680db71 100644
--- a/calc.py
+++ b/calc.py
@@ -37,16 +37,19 @@ class Calc(QMainWindow):
             self.pushButton_dot,
             self.pushButton_equal
         ]
-        map(lambda btn: btn.clicked.connect(self.click_on_button), btns)
+
+        for btn in btns:
+            btn.clicked.connect(self.click_on_button)
 
     def calculate(self):
         """
-        如果x、y、operater不为空，计算结果。
+        如果x、y、operater不为空，计算结果,计算出结果后，清空y,保持x和结果相等。
         """
         if self.x and self.y and self.operator:
             s = "%s%s%s"%(self.x,self.operator,self.y)
             print s
-            self.result =  str(eval(s))
+            self.x = self.result =  str(eval(s))
+            self.y = None
             self.text_result.setText(self.result)
 
     def click_on_button(self):
@@ -54,43 +57,50 @@ class Calc(QMainWindow):
         print "点击按钮前：" ,self.x,self.operator,self.y
         value  = self.sender().text()
         
-        # 如果点击的是数字，print该数字
+     
+        # 点击数字的处理：
+        # 1   点数字时，无运算符且有x，累加x
+        # 2   点数字时，有运算符且有y，累加y
+        # 3   点数字时，无运算符且无x，赋值给x
+        # 4   点数字时，有运算符且无Y，赋值给y
+    
         if value in "0123456789.":
-            print "您点击的数字是:",value
-            try:
-                if self.operator is  None:
-                # 如果点击的是数字的话，保存到x或追加到x
-                    if self.x is None:
-                        self.x = value
-                    else:
-                        self.x +=value
-                    self.text_result.setText(self.x)
+            if self.operator is not None:  #  有运算符
+                if self.y is not None:  #有y
+                    self.y =self.y + value
+                else:#无y
+                    self.y = value
+                self.text_result.setText(self.y)
+
+            else:#无运算符
+                if self.x is not None:#有x
+                    self.x = self.x + value
+
                 else:
-                    if self.y is None:
-                        self.y = value
-                    else:
-                        self.y +=value
-                    self.text_result.setText(self.y)
-            except Exception, e:
-                print e
-            
-
-            
-        #如果点击的是运算符，print该运算符
+                    self.x = value
+                self.text_result.setText(self.x)
+
+        
+        # 开始处理运算符
+        # 1.点运算符时记录运算符
+        # 2.点运算符时记录运算符并计算结果(x,y,oper都有值)
+        # 3.点运算符时记录运算符，并将x置为0(x无值)
+
         elif value in "+-*/":
-            print "print该运算符是：",value
             self.operator = value
-            self.text_result.setText("")
-
-        # 如果点击的是=，print  =
+            if self.x is None:
+                self.x = 0
+            if self.x and self.y and self.operator:
+                self.calculate()
 
-        elif value == '=':
-            print "您点击的是=。"
-            self.calculate()  
-            self.text_result.setText(self.result)          
-            
+        # 处理点击等号的操作
+        # 1.点等号时计算结果 (x,y,oper都有值）
+        # 2.点等号时忽略等号 (x,y,oper不都有值)
+       
+        elif value == "=":
+            if self.x and self.y and self.operator:
+                self.calculate()
 
-        # 若果点击的是clear，执行clear()方法
         else:
             print "您点击的是C"
             self.clear()