Computer Science - 4CP0 PearsonEdexcel

Develop Code

Gbogbo ọrọ náà

Getting a program to run is only the first hurdle. A program that produces the right answer for one test case, crashes on the next, and is unreadable to anyone but the person who wrote it, is not finished. Developing code properly means writing it clearly, testing it deliberately, and knowing exactly how to read the error messages Python gives you when something goes wrong.

This lesson covers the whole development cycle examined on both papers: writing readable Python, telling syntax, runtime and logic errors apart, designing a proper test plan, using trace tables to hunt down a bug, and judging a finished program's strengths and weaknesses. Every example uses Python, one of the three languages, alongside C# and Java, permitted for the Paper 2 practical exam.

Ebumnobi

Be able to write programs in a high-level programming language
Understand the benefit of producing programs that are easy to read and be able to use techniques (comments, descriptive names, indentation) to improve readability and to explain how the code works
Be able to differentiate between types of error in programs (logic, syntax, runtime)
Be able to design and use test plans and test data (normal, boundary, erroneous)
Be able to interpret error messages and identify, locate and fix errors in a program
Be able to determine what value a variable will hold at a given point in a program (trace table)
Be able to determine the strengths and weaknesses of a program and suggest improvements

Akọmọ Ojú-ẹkọ

It is entirely possible to write a program that produces the correct answer and is still poor code: unclear variable names, no comments, inconsistent indentation, and no thought given to what happens with unexpected input. Developing code is the process of getting from "it works once" to "it works reliably and anyone reading it can understand why".

Ọ dị na ngwa Green Bridge

Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.

Akwụkwọ ndụmọdụ zuru oke nwere eserese

Onye inyeaka mmụta AI

Mụọ n'ụzọ na-enweghị ịntaneti, oge ọbụla, ebe ọbụla

Budata ngwa ekwentị Budata ngwa kọmputa

Ọ dị na Android, Windows, macOS, na Linux

Ayẹwo Ẹkọ

Ekele diri gi maka imecha ihe karịrị na Develop Code. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

Which type of error prevents a program from running at all? A) Logic error B) Runtime error C) Syntax error D) Boundary error Answer: C
A program runs without crashing but consistently produces the wrong output. What type of error is this? A) Syntax error B) Runtime error C) Logic error D) Compilation error Answer: C
Which category of test data checks the exact edge of a valid range? A) Normal data B) Boundary data C) Erroneous data D) Random data Answer: B
A function tries to access index 10 of a list that only has 5 items. What type of error does this cause? A) Syntax error B) Runtime error C) Logic error D) No error, this is valid Answer: B
Which of these is a readability technique that does NOT change what a program computes? A) Using descriptive variable names B) Adding a missing loop C) Changing the algorithm used D) Adding an extra test case Answer: A