save project

my_search.py

@@ -11,4 +11,15 @@ def binary_search(alist,num):
     high = len(alist)-1
     while low <= high:
         mid = (low + high)
-        guess 
\ No newline at end of file
+        guess = alist[mid]
+        if guess == num:
+            return mid
+        elif guess < num:
+            low = mid + 1
+        else:
+            high = mid -1
+    return None 
+
+result = binary_search(alist,num)
+print("老师给的数是：",num)
+print("他在列表里的索引是：",result)
\ No newline at end of file