Worksheet 3: Thinking procedurally
Unit 10 Computational thinking
Worksheet 3 Thinking procedurally
1. You have been asked to write a procedure to count the number of vowels in a sentence.
How can you ensure that the procedure will work for any length of sentence?
2. To implement a stack, you would need three procedures: InitialiseStack(stack),
AddToStack(stack, item), RemoveFromStack(stack).
The identifiers in brackets are parameters defined in the main program and passed to the
procedure.
What procedures and parameters would you need to be able to implement a queue?
3. A hierarchy chart can be compared to an upside-down tree, with the root at the top and
branches and leaves spreading downwards.
The “leaves” are the lowest level modules and all or most of the detailed program code will
be in the “leaves”.
In the hierarchy chart below:
(a) Which are the Level 1 modules?
(b) Which are the Level 2 modules?
(c) Which are the Level 3 modules?
(d) Write down the order in which the modules are executed.
1
5
10
11
8
9
7
4
2
3
1
6
