python day1

求1-2+3-4+5 ... 99的所有数的和

 

sum1 = 0
sum2 = 0
count1 = 1
count2 = 0
while count1 <= 99:
    sum1 = sum1 + count1
    count1 = count1 + 2
#    print(sum1)
while count2 <= 99:
    sum2 = sum2 - count2
    count2 = count2 + 2
#    print(sum2)
sum = sum1 + sum2 

print(sum)

 修改后代码

count = 0
sum = 0
while count < 100:
    sum = sum - count
    count += 1
    sum = sum + count
    count += 1

print(sum )

 再次修改后代码

sum = 0
for i in range(0,100):
    if i % 2 == 0:
        sum = sum - i
    else:
        sum = sum + i
print(sum)