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diy1.py

-"""
-使用turtle模块画图
-每次移动都增加画笔移动的长度，并旋转91°，重复执行300次，查看效果
-"""
-import turtle
-
-pen = turtle.Pen()
-# 请创造师在下面接着创作
-distance = 1
-for i in range (300) :
-    pen.forward(distance)
-    distance+=1
-    pen.right(91)
-
-
-
-
-# 隐藏画笔，保存画布
-pen.hideturtle()
-turtle.done()
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+i = 2
+sum = 0
+while i<=100:
+    if i % 2 == 0:
+        sum -= i
+    else:
+        sum += i 
+    i +=1
+print('sum:',sum)
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