# 1. Is the following assignment statement valid or invalid?
# If it is invalid, why?
#72 = amount


# 2. What will the following code display?
val = 99
print('The value is', 'val')


# 3. Look at the following assignment statements
value1 = 99
value2 = 45.9
value3 = 7.0
value4 = 7
value5 = 'abc'
value6 = value1 + value2
value7 = 'value1' + 'value2'
value8 = 14 / 5
value9 = 14 // 5
value10 = 14 % 5
value11 = 10 * 3
value12 = '10' * 3
value13 = 10 ** 3
# value14 = '10' ** 3       # what is wrong?


# After these statement execute,
# what is the Python data type and values
# referenced by each variable?
print(type(value1), value1)
print(type(value2), value2)
print(type(value3), value3)
print(type(value4), value4)
print(type(value5), value5)
print(type(value6), value6)
print(type(value7), value7)
print(type(value8), value8)
print(type(value9), value9)
print(type(value10), value10)
print(type(value11), value11)
print(type(value12), value12)
print(type(value13), value13)
# print(type(value14), value14)   # What is wrong?



# 4. What will be displayed by the following program?
my_value = 99
print(type(my_value), my_value)
my_value = 'my_value'
print(type(my_value), my_value)
my_value = 99.0
print(type(my_value), my_value)
print(int(my_value))
print(str(my_value))
print(float(str(my_value)))
# print(int(str(my_value)))    # What is wrong?



# 5. What would the following code print?
def compare_things(a, z):
    if 'z' < 'a':
        print('z is less than a.')
    else:
        print('z is not less than a.')

compare_things(5, 3)


# 6. What would the following code print?
def compare_things2(a, z):
    if z < a:
        print(z, "is less than", a)
    else:
        print(z, "is not less than", a)

compare_things2(5, 3)


# 7. What would the following code print?
#    If there are errors, what are the errors?
#    How should the code be fixed?
# def compare_things3(a, z):
#     if z < a:
#         print(z + " is less than " + a)
#     else:
#         print(z + " is not less than " + a)
#
# compare_things3(5, 3)

# TypeError: unsupported operand type(s) for +: 'int' and 'str'
# To fix, cost a and z to string type
# def compare_things3(a, z):
#     if z < a:
#         print(str(z) + " is less than " + str(a))
#     else:
#         print(str(z) + " is not less than " + str(a))
#
# compare_things3(5, 3)


# 8. What would the following code print?
#    If there are errors, what are the errors?
#    How should the code be fixed?
def compare_things4(a, z):
    if z < a:
        print(z, "is less than", a)
    else:
        print(z, "is not less than", a)

compare_things4('5', '3')
# print("a = " + a + " and z = " + z)    # What is wrong?

# a and z are local variables
# To fix, make them of global scope, use the "global" keyword
# def compare_things4():
#     global a
#     global z
#     if z < a:
#         print(z, "is less than", a)
#     else:
#         print(z, "is not less than", a)
#
# a = '5'
# z = '3'
# compare_things4()
# print("a = " + a + " and z = " + z)


# 9. What would the following code print?
def compare_things5():
    global a
    global z
    z = 13
    if z < a:
        print(z, "is less than", a)
    else:
        print(z, "is not less than", a)

a = 5
z = 3
compare_things5()
print("a = " + str(a) + " and z = " + str(z))


# 10. Write a function that return the size of a given word.
#     For example, if the word is 'hello', the function
#     should return 5
def get_length(word):
    return len(word)

print(get_length('hello'))


# 11. What does the following code print
a = False
if not a:
    print('not a')
else:
    print('otherwise')




# good problem solving, function, and local and global practice
# but probably too much to ask for exam1
# 12. Write a function that return a factorial of a given number
def factorial(number):
    global result
    if number > 0:
        result = result * number
        number -= 1
        factorial(number)

    return result

result = 1     # why should result be initialized to 1
print(factorial(3))
result = 1     # reset it. why?
print(factorial(4))
result = 1
print(factorial(5))