实验4

实验任务1

print(sum)
sum=42
print(sum)

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

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

Q:不是

    line1:line1之前       line2:line2-3         line7:line6            line11:line10

实验任务2

 task2_2

list1=[19,8,4]

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

Q:是

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
    :para: a,b,c: int 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:
        a,b,c=eval(input('Enter eqution coefficient:'))
        if a==0:
            raise
    except:
        print('invalid input,or,a is zero')
        break
    else:
        root1,root2=solve(a,b,c)
        print(f'root1={root1:2f},root2={root2:.2f}')
        print()
        

task4

def list_generator(a,b,c=1):
    x=[]
    while a<=b:
        x.append(a)
        a+=c
    return x
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(a):
    for i in range(2,a):
        if a%i==0:
            return False
    else:
        return True
for i in range(4,21,2):
    for j in range(2,i):
        if is_prime(j) is True:
            if is_prime(i-j) is True:
                print(i,'=',j,'+',i-j)
                break

task6

def encoder(txt):
    txt_en=txt
    for i in txt_en:
        x=ord(i)
        if 65<=x<=90 or 97<=x<=122:
            if 65<=x+5<=90 or 97<=x+5<=122:
                txt_en=txt_en.replace(i,chr(x+5))
            else:
                txt_en=txt_en.replace(i,chr(x-21))
    return txt_en

def decoder(txt_en):
    txt_de=txt_en
    for i in txt_de:
        x=ord(i)
        if 65<=x<=90 or 97<=x<=122:
            if 65<=x-5<=90 or 97<=x-5<=122:
                txt_de=txt_de.replace(i,chr(x-5))
            else:
                txt_de=txt_de.replace(i,chr(x+21))
    return txt_de
    
txt=input('输入英语文本：')
print('编码后的文本：',encoder(txt))
txt_en=encoder(txt)
print('对编码后的文本解码：',decoder(txt_en))

task7