求1-2+3-4+5......99的所有数的和 

sum =0
count =1
while count <= 100:    
    if count%2==0:       
      sum=sum-count   
    else:      
       sum =sum + count    
       count +=1 
print(sum)
 

posted on 2018-12-25 15:51  没有岁月可回头  阅读(400)  评论(1)  编辑  收藏  举报