Year 11 · Computer Science · Summer 2
After the exams · Lesson 5 of 5
Course evaluation
Theory7.1 The program development life cycle
Year 11 · Computer Science · After the exams · Lesson 5 of 5
You will learn to
- Evaluate the course: what helped you learn, and what did not.
- Identify the hardest topic and the most useful lesson, with a reason for each.
- Suggest one change for next year's Year 11.
Year 11 · Computer Science · After the exams · Lesson 5 of 5
Success criteria
You have got it when you can say:
- I can give one specific example of something that helped me learn.
- I can name the hardest topic and say why it was hard.
- I can write one clear, kind suggestion for next year.
Year 11 · Computer Science · After the exams · Lesson 5 of 5
Retrieval starter
Questions from before. Write your answers, then show them.
- Last unit
In a trace table you write a new row…
A Only for OUTPUTB Only at the endC Each time a value changes
C. Each time a value changes
- Earlier this year
Which is a low-level language?
A PythonB JavaC Assembly language
C. Assembly language
- Last year
An interrupt is…
A A signal that makes the CPU pause and deal with somethingB A type of virusC A loop that never ends
A. A signal that makes the CPU pause and deal with something
Year 11 · Computer Science · After the exams · Lesson 5 of 5
Key words (1 of 3)
- Program development life cycle
- The four stages of making a program: analysis, design, coding and testing.
- Abstraction
- Removing details that do not matter so you can focus on the ones that do.
- Decomposition
- Breaking a problem into smaller parts that are easier to solve.
- Structure diagram
- A top-down diagram that shows how a system is split into sub-systems.
Year 11 · Computer Science · After the exams · Lesson 5 of 5
Key words (2 of 3)
- Flowchart
- A diagram of an algorithm using standard shapes joined by flow lines.
- Pseudocode
- A structured, code-like way of writing an algorithm that is not tied to one language.
- Check digit
- An extra digit calculated from the other digits, used to catch typing errors.
- Normal data
- Test data that should be accepted.
Year 11 · Computer Science · After the exams · Lesson 5 of 5
Key words (3 of 3)
- Abnormal data
- Test data that should be rejected.
- Extreme data
- The largest and smallest values that should be accepted.
The explanation · step 1 of 3 · part 1 of 3
Four stages, in order
The program development life cycle is the set of stages a programmer goes through to make a program.
There are four stages: analysis, design, coding and testing.
It is called a cycle because problems found in testing send you back to an earlier stage.
The explanation · step 1 of 3 · part 2 of 3
Four stages, in order (continued)
| Stage | Question it answers | What is produced |
|---|---|---|
| Analysis | What must the program do? | A list of requirements |
| Design | How will it do it? | Structure diagrams, flowcharts, pseudocode |
| Coding | Can we build it? | Program code, tested as it is written |
| Testing | Does it work for all data? | Test results with test data |
Planning before coding is faster overall. A mistake fixed in the design costs minutes. The same mistake found after coding can cost hours.
The explanation · step 1 of 3 · part 3 of 3
Four stages, in order (continued)
Learn the four names exactly. Cambridge uses analysis, design, coding, testing. Words like 'planning' or 'making' do not earn the mark.
The explanation · step 2 of 3 · part 1 of 3
Analysis: understand the problem
In analysis you find out exactly what the problem is and what the program must do. These needs are the requirements.
Abstraction means removing the details that do not matter, so you can focus on what does.
Decomposition means breaking a big problem into smaller parts that are easier to solve.
The explanation · step 2 of 3 · part 2 of 3
Analysis: understand the problem (continued)
The explanation · step 2 of 3 · part 3 of 3
Analysis: understand the problem (continued)
Abstraction stops you wasting time on details that will not affect the program. Decomposition turns one scary problem into several small, easy ones.
The explanation · step 3 of 3 · part 1 of 3
Design, coding and testing
In design you plan how the program will work. You decompose further and use structure diagrams, flowcharts and pseudocode.
In coding you write the program. You test each part as you write it. This is called iterative testing: write a bit, test it, fix it, repeat.
In testing you run the finished program with planned test data to check it works for every kind of input.
The explanation · step 3 of 3 · part 2 of 3
Design, coding and testing (continued)
The explanation · step 3 of 3 · part 3 of 3
Design, coding and testing (continued)
Do not mix up iterative testing and final testing. Iterative testing happens during coding, part by part. Final testing uses a full test plan on the finished program.
Year 11 · Computer Science · After the exams · Lesson 5 of 5
Homework and the challenge
Homework
None.
End-of-unit challenge
No test. A showcase.