实验4

task1

print(sum)
sum=42
print(sum)

def inc(n):
    sum=n+1
    print(sum)
    return sum

sum=inc(7)+inc(7)
print(sum)

1.打印sum函数

2.打印变量名为“sum”的变量

3.局部变量

4.全局变量

task2.2

list1=[1,9,8,4]

print(sorted(list1))
print(sorted(list1,reverse=True))
print(sorted(list1,True))

是的

task2.3

def func(a,b,c,/,*,d,e,f):
    return([a,b,c,d,e,f])
print(func(1,2,3,d=4,e=5,f=6))

task3

def solve(a,b,c):
    """
    求解一元二次方程，返回方程的两个根
    :param a,b,c: float 方程系数
    :return: tuple
    """
    delta=b*b-4*a*c
    delta_sprt=abs(delta)**0.5
    p1=-b/2/a
    p2=delta_sprt/2/a
    if delta >= 0:
        root1=p1+p2
        root2=p1-p2
    else:
        root1=complex(p1,p2)
        root2=complex(p1,-p2)
    return root1,root2
print(solve.__doc__)
while True:
    try:
        t=input('输入一元二次方程系数a b c,或者输入#结束：')
        if t =='#':
            print('计算结束，退出。')
            break
        a,b,c=map(float,t.split())
        if a==0:
            raise ValueError('a=0，不是一元二次方程。')
    except ValueError as e:
        print(repr(e))
        print()
    except:
        print('有其他错误发生\n')
    else:
        root1,root2= solve(a,b,c)
        print(f'root1={root1:.2f},root2={root2:.2f}')
        print()

task4

def list_generator(start,end,step=1):
    list=[start]
    i=start
    while i != end:
        i+=step
        list.append(i)
    return list

list1=list_generator(-5,5)
print(list1)
list2 = list_generator(-5, 5, 2)
print(list2)
list3 = list_generator(1, 5, 0.5)
print(list3)

task5

def is_prime(n):
    if n > 1:
        for i in range(2, int((n ** 0.5) + 1)):
            if n % i == 0:
                return False
        else:
            return True
    else:
        return False

num=4
while num<=20:
    for i in range(2,num):
        if is_prime(i):
            if is_prime(num-i):
                print(f'{num}={i}+{num-i}')
                break
    num+=2

task6

def encoder(text):
    text=list(text)
    i=0
    while i< len(text):
        if text[i].isalpha():
            if text[i].islower():
                if ord(text[i])<=117:
                    text[i]=chr(ord(text[i])+5)
                else:
                    text[i]=chr(ord(text[i])+5-26)
            if text[i].isupper():
                if ord(text[i])<=85:
                    text[i] = chr(ord(text[i]) + 5)
                else:
                    text[i] = chr(ord(text[i]) + 5 - 26)
        i+=1
    return ''.join(text)
def decoder(text):
    text = list(text)
    i = 0
    while i < len(text):
        if text[i].isalpha():
            if text[i].islower():
                if ord(text[i]) >= 102:
                    text[i] = chr(ord(text[i]) - 5)
                else:
                    text[i] = chr(ord(text[i]) - 5 + 26)
            if text[i].isupper():
                if ord(text[i]) >= 46:
                    text[i] = chr(ord(text[i]) - 5)
                else:
                    text[i] = chr(ord(text[i]) - 5 + 26)
        i += 1
    return ''.join(text)
for i in range(3):
    title='Remote Interpreter Reinitialized'
    print(title.center(60,'*'))
    text=input('输入英文文本：')
    encoded_text=encoder(text)
    decoded_text=decoder(encoded_text)
    print('编码后的文本：',encoded_text)
    print('对编码后的文本解码：',decoded_text)

task7

def collatz(number):
    if number % 2 == 1:
        return number * 3+1
    elif number % 2 ==0:
        return number // 2

for i in range(5):
    try:
        n = eval(input('Enter a positive integer:'))
        if type(n) is float or type(n) is str or n <= 0:
            raise ValueError('Error: must be a positive integer')
    except ValueError as e:
        print(repr(e))
        print()
    except:
        print('Error: must be a positive integer')
    else:
        num=collatz(n)
        list=[n,num]
        while True:
            if num != 1:
                num=collatz(num)
                list.append(num)
            elif num == 1:

                break
        print(list)

task8

def func(n):
    def func1(n):
        if n==0:
            return 1
        return 2*func1(n-1)
    return func1(n)-1

while True:
    x = input()
    if x == '#':
        print('计算结束')
        break
    n = int(x)
    ans = func(n)
    print(f'n = {n}, ans = {ans}')