如何使用 python 3.x 从用户输入中找到第二小/最大的数字？

Question

Very new to python, tried to complete a task which requires to find a summ of two biggest and two smallest numbers which were inputted by the user, the number 0 means the input is over, couldn't figure out why the code doesn't work

b = 0
c = 0
b2 = 0
c2 = 0
for i in range(-30000, 30000):
    a = int(input())
    if a == 0:
        break
    elif a > b:
        b = a
    elif a < c:
        c = a
    elif a >= b-1:
        b2 = a
    elif a <= c+1:
        c2 = a
print(b, b2, c, c2)
summ1 = b + b2
summ2 = c + c2
print(summ1, summ2)

b - biggest number, c - smallest number, b2 - second biggest number, c2 - second smallest number

After inputting the numbers and running the code the variables b2 and c2 are always 0, the biggest and smallest numbers work though

Answer 1

If a value is larger than b , you don't only have to set the new b but also move the old b to b2 :

    elif a > b:
        b, b2 = a, b
     
    elif a < c:
        c, c2 = a, c

    elif a >= b2:
        b2 = a
    elif a <= c2:
        c2 = a

The remaining elif statements were wrong. The number has to be higher than b2 or smaller than c2 .

Answer 2

I see that you are trying to learn Python here, so let me give you some general tips on how to solve your problem more simply:

1. First, collect all of the user input into a Python list
2. Now, find the largest 2 and smallest 2 numbers in that list. Remember that python has max() and min() functions.
3. Do the summing and printing

One quick python tip: Your for i in range(-30000, 30000): is really a "for forever:" In Python, we do that with while True: