实验4 函数与异常处理编程

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)

问题答案：不是。line1为内置作用域 ，line3和line11为全局作用域，line7为局部作用域

任务2_1

def func1(a, b, c, d, e, f):
    '''
    返回参数a,b,c,d,e,f构成的列表
    默认，参数按位置传递; 也支持关键字传递
    '''
    return [a, b, c, d, e, f]
 
def func2(a, b, c, *, d, e, f):
    '''
    返回参数a,b,c,d,e,f构成的列表
    *后面的参数只能按关键字传递
    '''
    return [a, b, c, d, e, f]
 
def func3(a, b, c, /, d, e, f):
    '''
    返回参数a,b,c,d,e,f构成的列表
    /前面的参数只能按位置传递
    '''
    return [a, b, c, d, e, f]
 
# func1调用：按位置传递、按参数传递都可以
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))
 
# func2调用：d,e,f必须按关键字传递
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) )
 
# func3调用：a,b,c必须按位置传递
print( func3(111, 999, 222, 0, 555, 333))
print( func3(111, 999, 222, d=0, e=555, f=333) )

任务2_2

list1 = [1, 9, 8, 4]
print( sorted(list1) )
print( sorted(list1, reverse=True) )
print( sorted(list1, True) )

问题答案：一定要用关键字传递

任务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):
    '''
    求解一元二次方程, 返回方程的两个根
    :para: a,b,c: float 方程系数
    :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('有其它错误发生\n')
    else:
        root1, root2 = solve(a, b, c)
        print(f'root1 = {root1:.2f}, root2 = {root2:.2f}')
        print()

任务4

def list_generator(x, y, s=1):
    l = []
    while x <= y:
        l.append(x)
        x = x+s
    return l
 
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(n):
    if n == 2:
        return True
    else:
        for i in range(2, int(n**0.5)+1):
            if n % i == 0:
                return False
        return True
 
for i in range(4, 21, 2):
    for s in range(2, i):
        if is_prime(i-s):
            print(f'{i} = {s} + {i-s}')
            break

任务6

# 编码函数encoder()定义
def encoder(a):
    c = ''
    for i in a:
        if i.isalpha():
            temp = ord(i)+5
            if chr(temp).isalpha():
                c += chr(temp)
            else:
                c += chr(temp-26)
        else:
            c += i
    return c
 
# 解码函数decoder()定义
def decoder(x):
    z = ''
    for i in x:
        if i.isalpha():
            temp = ord(i)-5
            if chr(temp).isalpha():
                z += chr(temp)
            else:
                z += chr(temp+26)
        else:
            z += i
    return z
 
# 主体代码逻辑
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):
    if n % 2 == 0:
        return n//2
    else:
        return n*3+1
 
try:
    n = int(input('Enter a positive integer:'))
    if n <= 0:
        raise ValueError
    num = [n]
    while True:
        n = Collatz(n)
        num.append(n)
        if n == 1:
 
            print(num)
            break
 
 
except ValueError:
    print('Error: must be a positive integer')

任务8

def func(n):
    while True:
 
        if n == 1:
            return 1
        else:
            return 2*func(n-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}')