实验4 函数与异常处理编程

实验结论

实验任务1

程序源代码

print(sum)
sum = 42
print(sum)
def inc(n):
    sum = n+1
    print(sum)
    return sum
sum = inc(7) + inc(7)
print(sum)

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问题回答：不是同一个对象的名称。line1是内置作用域，line3和line11是全局作用域，而line7是在inc中的局部作用域。

实验任务2

2-1程序源代码

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) )

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 在原line13后添加如下代码

print(func2(11,99,22,0,55,33))

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 在原line16后添加如下代码

print(func3(a=111,b=999,c=222,0,555,333))

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2-2程序源代码

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

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问题回答：内置函数sorted（）中，参数reverse一定要用关键字传递，不能使用位置传递方式。

2-3程序源代码

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))

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实验任务3

程序源代码

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

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('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()

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实验任务4

程序源代码

def list_generator(a,b,c=1):
    lst = []
    while a<=b:
        lst.append(a)
        a += c
    return lst

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

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实验任务5

程序源代码

def is_prime(n):
    if n == 2:
        return True
    elif True:
        for i in range(2,n):
            if n == 2:
                return True
            elif n % i == 0:
                break
            else:
                return True

for i in range(2,20+1,2):
    flag = True
    for j in range(2, i):
        if is_prime(j) == True and is_prime(i - j) == True and flag == True:
            print(f'{i}={j}+{i-j}')
            flag = False

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实验任务6

程序源代码

# 编码函数encoder()定义
def encoder(text):
    text_list = list(text)
    for i in range(len(text_list)):
        if ord('a') <= ord(text_list[i]) <= ord('z'):
            add5 = ord(text_list[i]) + 5
            if add5 <= ord('z'):
                text_list[i] = chr(add5)
            else:
                add5 = add5 % ord('z') - 1 +ord('a')
                text_list[i] = chr(add5)
        elif ord('A') <= ord(text_list[i]) <= ord('Z'):
            add5 = ord(text_list[i]) + 5
            if add5 <= ord('z'):
                text_list[i] = chr(add5)
            else:
                add5 = add5 % ord('Z') - 1 +ord('A')
                text_list[i] = chr(add5)
    return ''.join(text_list)

# 解码函数decoder()定义
def decoder(text):
    text_list = list(text)
    for i in range(len(text_list)):
        if ord('a') <= ord(text_list[i]) <= ord('z'):
            red5 = ord(text_list[i]) - 5
            if ord('a') <= red5:
                text_list[i] = chr(red5)
            else:
                red5 = ord('z') - (ord('a') - red5 - 1)
                text_list[i] = chr(red5)
        elif ord('A') <= ord(text_list[i]) <= ord('Z'):
            red5 = ord(text_list[i]) - 5
            if ord('A') <= red5:
                text_list[i] = chr(red5)
            else:
                red5 = ord('Z') - (ord('A') - red5 - 1)
                text_list[i] = chr(red5)
    return ''.join(text_list)

# 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)

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实验任务7

程序源代码

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))

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实验任务8

程序源代码

def func(n):
    if n == 0:
        return 0
    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}')

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