Functions calling other functions

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A function can call another function from inside its own body.

A True

B False

2. Which function follows the 'one job per function' idea?

A def do_everything(): ask, add up, print, save and quit

B def get_total(prices): return sum(prices)

3. In a program built from small functions, what is the job of main()?

A To call the other functions in the right order

B To do all of the work itself so other functions are not needed

4. Which is the correct way to have main() run a function called show_menu()?

A def main(): show_menu

B def main(): show_menu()

5. A hierarchy chart has a top box 'Play game' with two boxes below it: 'Get guess' and 'Check guess'. How could you turn these boxes into code?

A Make one function for each box. The top function calls the two below it.

B Put all three boxes into one big function with no other functions.

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1def main(): greet() show_score()		AThe function names are missing brackets (), so greet and show_score are never called
2total = add_tax(price)		BOne function is doing several jobs (asking, printing and scoring), so it is not one job per function
3Each box in a hierarchy chart can become its own function		Cdef main(): get_name() play_game() main()
4A main() function calls the other functions to run the whole program		Ddef draw_board(): print('Board')
5def main(): greet show_score		EA function call that uses the result of another function (add_tax) to do one part of the job
6def play(): ask_name() print(score()) def ask_name(): name = input() print(name) add_points(name)		Fmain() calls two smaller functions, greet() and show_score(), so each does one job

Definitions

def main():

Fill in the Blanks

Complete each line of code by filling in the missing parts.

___ main(): greet() show_score()

def ____(): print("Start") main()

def ______(n): return n * n def area(s): return square(s) print(area(4))

def main(): _____ = get_score() show_score(score)

# Chart box: Calculate total def _______________(): return 5 + 10

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A def get_name():

B return input('Name: '

C def main():

D name = get_name()

E print('Hi', name)

Question 2

A def double(n):

B n * 2

C def show(n):

D print(double(n))

E show(4)

Question 3

A def sq(n):

B return n * n

C def sum_sq(a, b)

D return sq(a) + sq(b)

Question 4

A def main():

B print('Start')

C greet

D def greet():

E print('Hello!')

F main()

Question 5

A def get_score():

B return 80

C def show():

D print(getscore())

E show()

Answer Key

Functions calling other functions

Section A: Quick Questions

A — True

B — def get_total(prices): return sum(prices)

A — To call the other functions in the right order

B — def main(): show_menu()

A — Make one function for each box. The top function calls the two below it.

Section B: Match the Pairs

def main(): greet() show_score() → main() calls two smaller functions, greet() and show_score(), so each does one job

total = add_tax(price) → A function call that uses the result of another function (add_tax) to do one part of the job

Each box in a hierarchy chart can become its own function → def draw_board(): print('Board')

A main() function calls the other functions to run the whole program → def main(): get_name() play_game() main()

def main(): greet show_score → The function names are missing brackets (), so greet and show_score are never called

def play(): ask_name() print(score()) def ask_name(): name = input() print(name) add_points(name) → One function is doing several jobs (asking, printing and scoring), so it is not one job per function

Section C: Definitions

def main(): — A function that calls other small functions, each doing one job, so the program is built in parts. Each box in a hierarchy chart can become one function.

Section D: Fill in the Blanks

def main():
    greet()
    show_score()

def main():
    print("Start")
main()

def square(n): return n * n
def area(s): return square(s)
print(area(4))

def main():
    score = get_score()
    show_score(score)

# Chart box: Calculate total
def calculate_total():
    return 5 + 10

Section E: Spot the Error

B — The closing bracket of input() is missing. The line should be return input('Name: ') so the function gives back what the user typed.

B — double() works out n * 2 but never returns it, so it gives back None. The line should be return n * 2 so show() can use the result.

C — A function definition must end with a colon. It should be def sum_sq(a, b): so the body can call sq() twice.

C — Without brackets, greet is just the name of the function and it is not called. It should be greet() so main() runs the greet function.

D — The function is called get_score, not getscore. Function names must match exactly when one function calls another.