Class 8 Computer Science — Procedures, and calling them

Read a program that gives a block of lines a name, and say what runs, when, and how many times.

Name: ________________________

1.This program prints four numbers. Put them in the order they appear on the screen.
```
def middle():
    print(9)
    print(5)

print(7)
middle()
print(1)
```
- 1
- 9
- 5
- 7
2.The named block has a loop inside it. How many numbers does it print?
```
def show():
    for n in range(1, 4):
        print(n)

show()
show()
```
3.A procedure whose body is a single printing line is used in five different programs. Match each way of using it to how many times its body runs.
- Defined but never called
- Called once at the end of the program
- Called inside a loop over range(1, 6)
- Called twice, and again inside a loop over range(1, 5)
- Called inside a loop over range(1, 3) that itself sits inside a loop over range(1, 5)
- 1
- 5
- 6
- 8
- 0
4.Follow this code by hand. How many times does the line printing 3 run?
```
def step():
    print(3)

for n in range(1, 5):
    step()
```
5.Read this program from the top down. How many numbers does it print?
```
def show():
    print(5)
```
- a) 0
- b) It cannot be run at all
- c) 5
- d) 1

6.One named block calls another. How many numbers does it print?

def inner():
    print(1)

def outer():
    inner()
    inner()

outer()

8.A loop calls a block that calls another block. How many numbers does it print?

def inner():
    print(1)

def outer():
    inner()
    inner()

for n in range(1, 5):
    outer()

Answer key — Class 8 Computer Science — Procedures, and calling them

1. 1. 7 2. 9 3. 5 4. 1
2. 6
3. Defined but never called → 0; Called once at the end of the program → 1; Called inside a loop over range(1, 6) → 5; Called twice, and again inside a loop over range(1, 5) → 6; Called inside a loop over range(1, 3) that itself sits inside a loop over range(1, 5) → 8
4. 4
5. a) 0
6. 2
7. 4
8. 8