AP Computer Science Principles-øveprøve
- 15 spørgsmål
- Cirka 15 min.
- Gratis
Testens spørgsmål er på engelsk.
A student's program that averages three test scores runs without any error message, but it always reports an average that is too high. The code adds the three scores and divides by 2 instead of 3. What kind of error is this?
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Om denne test
Det her er en gratis smagsprøve på 15 spørgsmål i stil med multiple choice-delen af AP Computer Science Principles, skrevet af StudyPDF-teamet ud fra de fem Big Ideas, som College Board offentliggør for faget. Den dækker kreativ udvikling, data, algoritmer og programmering i pseudokode som på den rigtige prøve, computersystemer og netværk samt computerteknologiens betydning for samfundet, nogenlunde i de vægte, prøven bruger. Du møder multiple choice, vælg alle der passer og udfyld det tomme felt. Svar på alle 15, se så din score og læs forklaringen til hvert spørgsmål.
Alle 15 spørgsmål i overblik
Vil du hellere læse, før du går i gang? Alle spørgsmål i smagsprøven står herunder. Svar og forklaringer er foldet sammen, indtil du åbner dem.
1.A student's program that averages three test scores runs without any error message, but it always reports an average that is too high. The code adds the three scores and divides by 2 instead of 3. What kind of error is this?
- A. Syntax error
- B. Logic error
- C. Overflow error
- D. Run-time error
Svar: B. Logic error
A logic error is a mistake in the algorithm: the program runs and produces a result, but the result is wrong. A syntax error breaks the rules of the language, so the program will not run at all. A run-time error stops the program while it is running, for example by dividing by zero, and an overflow error happens when a value is too large for the number of bits the computer uses to store it. Logic errors are the hardest to find because nothing crashes, which is why testing with inputs whose answer you already know matters.
2.Which practices are part of an iterative, collaborative way to develop a program?
Vælg alle, der passer.
- A. Building a small working version, testing it with users and revising it
- B. Having teammates review each other's code to catch errors and bring different perspectives
- C. Writing the whole program before running it even once, so nothing half-finished confuses the team
- D. Writing comments and documentation that explain what a code segment is for
- E. Keeping the design secret from users until the final version is done
Svar: A. Building a small working version, testing it with users and revising it, B. Having teammates review each other's code to catch errors and bring different perspectives, D. Writing comments and documentation that explain what a code segment is for
Iterative development means building, testing and refining in small steps, so mistakes show up early and feedback shapes the next version. Collaboration brings in other viewpoints, and people with different backgrounds notice different problems and needs. Documentation helps teammates, and your future self, understand what code was meant to do. Writing everything before the first run lets errors pile up, and hiding the design from users removes the feedback the process depends on.
3.Complete the sentence.
In binary, the number 1011 equals _____ in decimal, and a sequence of 8 bits can represent _____ different values.
Muligheder for felt 1: 9, 11, 13, 15
Muligheder for felt 2: 16, 128, 255, 256
Svar: 11, 256
Each binary place is worth twice the one to its right: 8, 4, 2, 1. So 1011 is 8 + 0 + 2 + 1 = 11. With n bits there are 2 to the power n different patterns, and 2^8 = 256, so 8 bits can represent 256 different values, from 0 through 255. The 255 option is the largest number that fits in 8 bits, not the count of values, and that off-by-one is a classic trap.
4.A museum is compressing scans of old documents and must be able to rebuild every original pixel exactly. Which approach should it use?
- A. Lossless compression
- B. Lossy compression with the quality set to high
- C. Lossy compression after deleting every second row of pixels
- D. Any compression, since a rebuilt file always matches the original
Svar: A. Lossless compression
Lossless compression reduces file size in a way that lets the original data be reconstructed exactly, which is what an archive needs. Lossy compression gets smaller files by throwing information away for good, and even at high quality the original cannot be rebuilt. Lossy is a sensible trade for streaming video or casual photos, where small differences are hard to see. The cost of lossless is that files stay larger.
5.A phone photo file includes the date, the GPS location and the camera model along with the image itself. Which statement is correct?
- A. Metadata is the part of the image that is lost when the photo is compressed
- B. Metadata can only be created by the person who views the file
- C. Metadata changes the pixels of the image every time the photo is copied
- D. Metadata is data about other data, and it can reveal private details even if you only share the photo
Svar: D. Metadata is data about other data, and it can reveal private details even if you only share the photo
Metadata describes a piece of data without being the data itself: when a photo was taken, where, with what device. It helps people organize and search large collections, and it can be changed or deleted without changing the image. It can also expose things the sender never meant to share, such as a home location, so many apps remove it on upload. Metadata is not lost by compression and does not alter the pixels.
6.total ← 0. FOR EACH item IN [3, 8, 12, 5, 10], IF (item MOD 2 = 0), then total ← total + item. After the loop, DISPLAY(total). What is displayed?
- A. 8
- B. 10
- C. 30
- D. 38
Svar: C. 30
item MOD 2 is the remainder when item is divided by 2, so the test is true only for even numbers. The even items are 8, 12 and 10, and 8 + 12 + 10 = 30. The 38 answer adds every item, as if the test were missing, and 8 is the sum of the odd items, 3 + 5. When you trace a loop, write the value of total after each pass, so the one skipped odd number is easy to see.
7.nums ← [4, 8, 15, 16]. Then INSERT(nums, 2, 23), REMOVE(nums, 1) and APPEND(nums, 42) run in that order. List positions start at 1. What does DISPLAY(nums[3]) show?
- A. 8
- B. 15
- C. 16
- D. 23
Svar: B. 15
Trace the list after each step. Start with [4, 8, 15, 16]. INSERT at position 2 puts 23 there and shifts the rest right: [4, 23, 8, 15, 16]. REMOVE position 1 deletes the 4: [23, 8, 15, 16]. APPEND adds 42 at the end: [23, 8, 15, 16, 42]. Position 3 holds 15. The 8 answer comes from forgetting that INSERT shifts items, and 16 comes from counting positions from 0 instead of 1.
8.Complete the sentence.
Suppose p is true and q is false. Then p AND (NOT q) evaluates to _____, and NOT (p OR q) evaluates to _____.
Muligheder for felt 1: true, false
Muligheder for felt 2: true, false
Svar: true, false
Work from the inside out. NOT q is true because q is false, so p AND (NOT q) is true AND true, which is true. For the second one, p OR q is true OR false, which is true, and NOT true is false. AND is true only when both sides are true, OR is true when at least one side is, and NOT flips the value. Writing each sub-result on its own line prevents most mistakes.
9.Which statements about algorithms are true?
Vælg alle, der passer.
- A. Every algorithm can be built from sequencing, selection and iteration
- B. A faster computer can make any undecidable problem solvable
- C. Two different algorithms can solve the same problem while using very different numbers of steps
- D. A heuristic can be used when finding the best solution would take an unreasonable amount of time
- E. An algorithm whose steps double with every added input is the best choice for very large inputs
Svar: A. Every algorithm can be built from sequencing, selection and iteration, C. Two different algorithms can solve the same problem while using very different numbers of steps, D. A heuristic can be used when finding the best solution would take an unreasonable amount of time
Sequencing, selection and iteration are enough to express any algorithm. Different algorithms for one problem can differ hugely in efficiency, which is why comparing step counts matters. A heuristic gives a good-enough answer in reasonable time when the exact answer is out of reach. An undecidable problem has no algorithm that works for every input, however fast the machine, and a step count that doubles with each added input quickly becomes unusable, since it is not a reasonable-time algorithm.
10.A city engineer uses a computer simulation of rush-hour traffic to test new traffic light timing before changing the real intersection. Which statement about the simulation is accurate?
- A. It is always more reliable than watching the real intersection, because a simulation never leaves anything out
- B. It cannot be used until the real intersection has been rebuilt
- C. It removes the need for any data about real traffic
- D. It lets the city test changes without cost or risk, but the results depend on what the model left out
Svar: D. It lets the city test changes without cost or risk, but the results depend on what the model left out
A simulation is an abstraction: it keeps the details that matter for the question and leaves the rest out. That makes it cheap and safe to try ideas, such as many timings in an afternoon, which would be impractical on a real street. The limit is that the results are only as good as the model and the data behind it, so a factor left out, such as a road closure, can make the real outcome differ. That is why simulation results are checked against real observations.
11.A school network connects each building to at least two others, so students can still reach the Internet if one cable is cut. Which statement best describes this design?
- A. It is fault tolerant, because redundant paths keep the network working after a failure
- B. It has higher bandwidth, because each cable carries more data
- C. It has lower latency, because messages always take the shortest path
- D. It is encrypted, because messages cannot be read in transit
Svar: A. It is fault tolerant, because redundant paths keep the network working after a failure
The Internet is built to be fault tolerant: there are usually several paths between two points, so routing can send data around a broken link. Extra connections do not by themselves raise bandwidth, which is how much data can move per second, and an alternate path can even be longer. Encryption is about privacy, not about surviving a failure. Redundancy is the key word for this kind of question.
12.Complete the sentence.
The Domain Name System (DNS) looks up a _____ such as example.org and returns the matching _____, which routers use to deliver packets.
Muligheder for felt 1: packet, domain name, protocol, password
Muligheder for felt 2: IP address, bit rate, file format, encryption key
Svar: domain name, IP address
People use names such as example.org because they are easy to remember, but routers move data by IP address. DNS is the lookup service that translates a domain name into the IP address of the server. Without it you would have to type numbers to visit a site. A packet is a small chunk of data that travels the Internet, and a protocol is an agreed set of rules, such as TCP and IP.
13.A company trains a program to screen job applications using the records of people it hired over the past 20 years, most of whom came from a few similar backgrounds. Which concern is most likely?
- A. The program will be fair, because computers cannot have bias
- B. The program cannot run, because applications are not binary data
- C. The program may repeat the pattern in the old hiring data, which is a form of computing bias
- D. The program will only improve if the old records are deleted after training
Svar: C. The program may repeat the pattern in the old hiring data, which is a form of computing bias
Computing bias can come from the data a program learns from or from choices its designers make. A model trained on past decisions can copy their patterns, including unfair ones, and it can do so at scale and with an air of objectivity. Computers do not make bias impossible, and all digital data, including text, is stored in binary. Reducing bias takes steps such as checking results across groups and using more representative data, not deleting records.
14.Which actions help protect an online account from being taken over?
Vælg alle, der passer.
- A. Turning on multifactor authentication
- B. Reusing one strong password on every site so it is easy to remember
- C. Treating a message that asks you to log in through a link with suspicion, since phishing tries to trick you into giving up your login
- D. Using a different, long password for each account, ideally with a password manager
- E. Sharing the one-time login code with anyone who says they work for support
Svar: A. Turning on multifactor authentication, C. Treating a message that asks you to log in through a link with suspicion, since phishing tries to trick you into giving up your login, D. Using a different, long password for each account, ideally with a password manager
Multifactor authentication requires a second proof besides the password, so a stolen password alone is not enough. Phishing is an attempt to trick people into entering credentials on a fake page, so going to the site directly beats clicking a link in a message. Unique passwords limit the damage if one site is breached, and a password manager makes them practical. Reusing a password lets one breach open many accounts, and a one-time code is meant for you alone, so no legitimate support team asks for it.
15.Maria publishes her public key. Devon wants to send her a message that only she can read, using public-key encryption. Which key does Devon use to encrypt it?
- A. Devon's private key
- B. Devon's public key
- C. Maria's private key
- D. Maria's public key
Svar: D. Maria's public key
In public-key encryption each person has a pair of keys. Anyone can use Maria's public key to encrypt a message to her, but only her private key can decrypt it, so only she can read it. Devon's own keys are not involved in this direction. The private key must never be shared, which is the whole point of the pair. Public keys are what let a browser start a secure connection with a site it has never met.
Hvordan AP CSP-prøven ser ud, og hvordan Big Ideas vægtes
AP Computer Science Principles-prøven scores fra 1 til 5 og har to dele. Ifølge College Board er afslutningsprøven fuldt digital i Bluebook-appen. Section I er 70 multiple choice-spørgsmål på 120 minutter og tæller 70 procent af din score, med fire svarmuligheder hver: 57 har ét rigtigt svar, 5 har ét rigtigt svar og bygger på en tekst om en computerteknologisk nyskabelse, og 8 har flere rigtige svar, hvor du vælger 2. Section II tæller de sidste 30 procent. Den kombinerer Create performance task med 2 skriftlige spørgsmål, 4 opgaver i alt, som du besvarer i en del af prøvedagen på 60 minutter, og som handler om dit eget program.
College Board deler faget i fem Big Ideas og offentliggør, hvor meget af prøvescoren hver af dem giver. Algoritmer og programmering fylder mest med 30 til 35 procent. Computerteknologiens betydning er 21 til 26 procent, data er 17 til 22 procent, computersystemer og netværk er 11 til 15 procent, og kreativ udvikling er 10 til 13 procent. Cirka en tredjedel af prøven handler altså om algoritmer og programmering, en stor del af det om at læse og følge kode, og cirka en fjerdedel handler om computerteknologiens betydning for mennesker, som er den del, eleverne oftest gemmer til sidst.
College Board har sat 2027-prøven til fredag den 14. maj i Session 1, og Create performance task skal være afleveret som endelig i AP Digital Portfolio senest fredag den 30. april kl. 23.59 ET. Datoer ændrer sig fra år til år, så tjek College Boards side for dit eget prøveår. Hvad en score giver, bestemmer hvert enkelt college selv, så slå reglerne op på de skoler, der interesserer dig.
Sådan bruger du smagsprøven, og hvad den ikke dækker
De 15 spørgsmål fordeler sig på Big Ideas i omtrent samme forhold som på prøven: fem om algoritmer og programmering, tre om data, tre om computerteknologiens betydning, to om computersystemer og netværk og to om kreativ udvikling. De spørger mere til ræsonnementet bag et svar end til et udenadslært begreb: hvorfor et program, der kører, stadig kan være forkert, hvorfor tabsfri komprimering er det rigtige værktøj, når hver eneste pixel tæller, hvorfor en simulation er nyttig og alligevel begrænset, og hvorfor en model, der er trænet på gamle data, kan gentage gammel uretfærdighed.
Kodespørgsmålene bruger pseudokode i ren tekst i samme stil som på prøven. En pil betyder tildeling, så x ← 3 gemmer 3 i x. Lister starter på position 1, ikke 0, og MOD giver resten af en division. Prøven bruger sin egen pseudokode, ikke Python eller Java, så du kan øve den, selv om din klasse arbejder i et andet sprog. Tag den i ét stræk med kladdepapir, følg hvert program ved at skrive værdien af hver variabel ned efter hver linje, og læs så forklaringen til hvert spørgsmål, også dem du svarede rigtigt på.
Smagsprøven øver ikke Create performance task. Det er det program, du bygger i timerne over cirka 9 timer, med koden, en kort video af det kørende program og en Personalized Project Reference, og dine skriftlige svar på prøvedagen handler om det samme program. Arbejd med det sammen med din lærer og College Boards håndouts til eleverne, og brug spørgsmålene her som øvelse til multiple choice-delen alene. Spørgsmålene er originale og skrevet til det offentliggjorte fagindhold. De er ikke frigivne prøvespørgsmål.
Sådan bygger StudyPDF AP CSP-øveprøver ud fra dine noter
Femten spørgsmål kan vise dig, hvilken Big Idea der er svag. De kan ikke gøre dig klar alene, og en generisk bank rammer sjældent de begreber, eksempler og den pseudokode, din lærer faktisk bruger.
StudyPDF tager i stedet udgangspunkt i dit materiale. Upload dine noter fra timerne, din lærers slides, et gennemgået opgavesæt eller din repetitionspakke, tryk på Nyt materiale, og StudyPDF bygger øveprøver ud fra præcis de sider. Hvert spørgsmål bygger på dit materiale, og hver forklaring henviser til, hvor svaret kommer fra, så du kan gå direkte tilbage til siden, når et trin ikke giver mening.
Du behøver ikke uploade noget for at komme i gang. Nævn i stedet et emne, for eksempel internettet og DNS eller lister og iteration, så sætter Bo det op med de vigtigste begreber, og du kan bygge quizzer og flashcards om det. Dine resultater viser, hvilke begreber du bliver ved med at ramme forkert, så den næste øveprøve kan ramme dem. Det er gratis at komme i gang.
Skrevet af StudyPDF-teamet. Sidst opdateret 19. august 2026.
Godt at vide
Er denne AP Computer Science Principles-øveprøve virkelig gratis?
Ja. Alle 15 spørgsmål, scoreskærmen og hver eneste forklaring er gratis at spille i din browser, og der er ingen betalingsmur på denne side.
Hvordan er AP CSP-prøven bygget op?
Ifølge College Board er Section I 70 multiple choice-spørgsmål på 120 minutter og tæller 70 procent af din score. Section II tæller 30 procent og kombinerer Create performance task, som du bygger i timerne over cirka 9 timer, med 2 skriftlige spørgsmål i en del af prøvedagen på 60 minutter. Prøven tages i Bluebook-appen. Tjek College Boards side for den aktuelle prøvedato.
Hvem har skrevet spørgsmålene, og dækker de Create-opgaven?
StudyPDF-teamet har skrevet hvert spørgsmål og hver forklaring ud fra de Big Ideas, College Board offentliggør for faget. De er ikke frigivne prøvespørgsmål, og de er ikke taget fra en forberedelsesudbyders bank. Create performance task øves ikke her, fordi det er et program, du bygger selv. StudyPDF er ikke tilknyttet College Board, og AP er et varemærke tilhørende College Board.
Kan jeg få flere spørgsmål som disse ud fra mine egne noter?
Ja. Upload dine noter fra timerne, slides eller din repetitionspakke til StudyPDF, så bygger Bo fulde øveprøver ud fra præcis de sider, med forklaringer der henviser til, hvor hvert svar kommer fra. Har du kun noget på papir, så nævn et emne i stedet, for eksempel lister og iteration, så skriver Bo en prøve ud fra det.
Har du brug for mere end en smagsprøve?
Upload din egen eksamensbog, dine slides eller noter, så bygger Bo fulde øveprøver ud fra præcis dit materiale, holder styr på de begreber du bliver ved med at ramme forkert, og går efter dine svage punkter. Gratis at komme i gang.