### ex5-1 ###

a = int(input('Enter an interger: '))

if a < 1:
    a += 1
    b = a + 3

print(b)



### ex5-2 (5-1.py) ###

num = int(input('Enter a number: '))

if num > 0:
    print('num is positive')

print('finished comparing num to 0')



### ex5-3 (5-2.py) ###

num_a = int(input('Pick a number: '))

if num_a > 0:
    print('Your number is positive')

if num_a < 0:
    print('Your number is negative')

if num_a == 0: 
    print('Your number is zero')

print('Finished!')



### ex5-4 ###

# 巢狀條件式 (5-3a.py)
num_a = int(input('Number? '))
num_b = int(input('Number? '))

if num_a < 0:      
    print('num_a is negative')
    if num_b < 0:
        print('num_b is negative')

print('Finished')



# 非巢狀條件式 (5-3b.py)
num_a = int(input('Number? '))
num_b = int(input('Number? '))

if num_a < 0:      
    print('num_a is negative')

if num_b < 0:
    print('num_b is negative')

print('Finished')



### ex5-5 (5-4.py) ###

price = float(input('How much does a chocolate bar cost? '))
hungry = input('Are you hungry (yes or no)? ')
bars = 0

if hungry == 'yes': 
    if price < 10:
        print('Buy all chocolate bars.')
        bars = 100
    if 10 <= price <= 50:
        print('Buy 10 chocolate bars.')     
        bars = 10
    if price > 50:
        print('Buy only one chocolate bar.')
        bars = 1

if hungry == 'no':
    print('Stick to the shopping list.')

if bars > 10:
    print("Cashier says: someone's hungry!")



### ex5-6 ###

# 多條件運算式 (5-5a.py)
num_a = int(input('Number? '))
num_b = int(input('Number? '))

if num_a < 0 and num_b < 0: 
    print('both negative')



# 巢狀條件式 (5-5b.py)
num_a = int(input('Number? '))
num_b = int(input('Number? '))

if num_a < 0:
    if num_b < 0:
        print('both negative')



### ex5-7 (5-6.py) ###

Num = int(input('please pick a number: '))

if Num % 2 == 0:
    print('Even Number')
else:
    print('Odd Number')



### ex5-8 (5-7.py) ###

num = int(input('Enter a number: '))

if num > 0:
    print('num is positive')
elif num < 0:
    print('num is negative')
else:
    print('num is zero')



### ex5-9 (5-8.py) ###

num_a = int(input('pick a number: '))
num_b = int(input('pick another number: '))
lucky_num = 7

if num_a == num_b:
    print('You enter the same number')
else:
    if num_a > 0 and num_b > 0:
        print('both numbers are positive')
    elif num_a < 0 and num_b < 0:
        print('both numbers are negative')
    else:
        print('numbers have opposite sign')

if num_a == lucky_num or num_b == lucky_num:
    print('you also guessed my lucky number!')
else:
    print('I have a secret number in mind...')



### ex5-10 (5-9.py) ###

num_a = int(input('pick a number: '))
num_b = int(input('pick another number: '))
lucky_num = 7

if num_a == num_b:
    print('You enter the same number')
elif num_a > 0 and num_b > 0:
    print('both numbers are positive')
elif num_a < 0 and num_b < 0:
    print('both numbers are negative')
else:
    print('numbers have opposite sign')

if num_a == lucky_num or num_b == lucky_num:
    print('you also guessed my lucky number!')
else:
    print('I have a secret number in mind...')



### ex5-11 (5-10.py) ###

greeting = input('Say hi in English or Spanish! ')
greet_en = ('hi', 'Hi', 'hello', 'Hello')
greet_sp = ('hola', 'Hola')

if greeting not in greet_en and greeting not in greet_sp:
    print("I don't understand your greeting.")
elif greeting in greet_en:
    num = int(input('Enter 1 or 2: '))
    print('You speak English!')

    if num == 1:
        print('one')
    elif num == 2:
        print('two')

elif greeting in greet_sp:
    num = int(input('Enter 1 or 2: '))
    print('You speak Spanish!')

    if num == 1:
        print('uno')
    elif num == 2:
        print('dos')