实验四

任务1

print(sum)
sum=42
print(sum)

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

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

任务2

2.1

def func1(a,b,c,d,e,f):
    return[a,b,c,d,e,f]

def func2(a,b,c,*,d,e,f):
    return [a,b,c,d,e,f]

def func3(a,b,c,/,d,e,f):
    return[a,b,c,d,e,f]

print(func1(1,9,2,0,5,3))
print(func1(a=1,b=9,c=2,d=0,e=5,f=3))
print(func1(1,9,2,f=3,d=0,e=5))

print(func2(11,99,22,d=0,e=55,f=33))
print(func2(a=11,b=99,c=22,d=0,e=55,f=33))

print(func3(111,999,222,0,555,333))
print(func3(111,999,222,d=0,e=555,f=333))

2.2

list1=[1,9,8,4]

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

2.3

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))

任务3

def solve(a,b,c):
    '''
    :para:a,b,c:float
    :return:tuple'''
    delta=b*b-4*a*c
    delta_sqrt=abs(delta)**0.5
    p1=-b/2/a
    p2=delta_sqrt/2/a

    if delta>=0:
        root1=p1+p2
        root2=p1-p2
    else:
        root1=complex(p1,p2)
        root2=complex(p1,-p2)

    return root1,root2

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('结束计算，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()

 任务4

  # list_generator()函数定义
def list_generator(start, stop, step=1):
     result = []
     i = start
     while i <= stop:
         result.append(i)
         i += step
     return result


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

任务5

def is_prime(x):
    for i in range(2,int(x**0.5+2)):
       a=x%i
       if a==0:
            break
    if a==0 and x!=2:
         return False
    elif a!=0 or x==2:
        return True


for i in range(4,21,2):
     for x in range(2,i):
         y = i - x
         if is_prime(x) and is_prime(y):
            print(f'{i}={x}+{y}')
            break

任务6

def encoder(text):
     x1 = ''
     for i in text:
        if 'a' <= i <= 'z':
            i = chr((ord(i)-97+5) % 26 + 97)
            x1 += i
        elif 'A' <= i <= 'Z':
            i = chr((ord(i)-65+5) % 26 + 65)
            x1 += i
        else:x1 += i
     return x1


def decoder(text):
     x2 = ''
     for i in text:
         if 'a' <= i <= 'z':
             i = chr((ord(i)-97-5) % 26 + 97)
             x2 += i
         elif 'A' <= i <= 'Z':
             i = chr((ord(i)-65-5) % 26 + 65)
         x2 += i
     else:
             x2 += i
     return x2


text = input('输入英文文本: ')
encoded_text = encoder(text)
print('编码后的文本: ', encoded_text)
decoded_text = decoder(encoded_text)
print('对编码后的文本解码: ', decoded_text)

任务7

def collatz(n):
   lst = []
   lst.append(n)
   while n != 1:
        if n %2 == 0:
            n = n/2
            lst.append(int(n))
        else:
            n = n*3 +1
            lst.append(int(n))
   return lst
try:
    n = int(input('Enter a positive integer:'))
    if n <= 0:
       raise ValueError
except ValueError:
    print('Error: must be a positive integer')
else:
    print(collatz(n))

任务8

def func(a):
    if a==0:
        return 0
    else:
        return 2*func(a-1)+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}')