answer string | choices dict | id string | kind string | lang string | question string | steps list | subject string | text string | topic string |
|---|---|---|---|---|---|---|---|---|---|
dict.get returns the default 0 when the key is missing. | null | cs_0051 | worked_example | en | What does {'a':1}.get('b',0) return? | [
"Key 'b' missing.",
"Default 0 applies.",
"Returns 0."
] | computer_science | Answer: 0.
Steps:
1. Key 'b' missing.
2. Default 0 applies.
3. Returns 0. | python |
Slicing takes [start:stop:step] with stop excluded. | null | cs_0052 | concept | en | How does Python slicing work? | [
"Start included.",
"Stop excluded.",
"Step skips items."
] | computer_science | Answer: [start:stop:step].
Steps:
1. Start included.
2. Stop excluded.
3. Step skips items. | python |
Řez 'abcdef'[1:4] dá 'bcd'. | null | cs_0053 | worked_example | cs | Co vrátí 'abcdef'[1:4]? | [
"Indexy 1 až 3.",
"Znaky b, c, d.",
"Výsledek 'bcd'."
] | computer_science | Answer: 'bcd'.
Steps:
1. Indexy 1 až 3.
2. Znaky b, c, d.
3. Výsledek 'bcd'. | python |
range(3) yields 0, 1, 2. | {
"A": "0, 1, 2",
"B": "1, 2, 3",
"C": "0, 1, 2, 3",
"D": "3, 2, 1"
} | cs_0054 | multiple_choice | en | What does range(3) produce? | [
"Starts at 0.",
"Stops before 3.",
"Select option A."
] | computer_science | Answer: 0, 1, 2.
Steps:
1. Starts at 0.
2. Stops before 3.
3. Select option A.
Answer: (A) | python |
Functions are defined with def and send values back via return. | null | cs_0055 | concept | en | How are Python functions defined? | [
"Use def keyword.",
"Name parameters.",
"Return the result."
] | computer_science | Answer: def with return.
Steps:
1. Use def keyword.
2. Name parameters.
3. Return the result. | python |
f(3) = 3**2 + 1 = 10. | null | cs_0056 | worked_example | en | If f(x) = x**2 + 1, what is f(3)? | [
"Square: 3**2 = 9.",
"Add 1.",
"Result = 10."
] | computer_science | Answer: 10.
Steps:
1. Square: 3**2 = 9.
2. Add 1.
3. Result = 10. | python |
The def keyword defines a Python function. | {
"A": "fun",
"B": "function",
"C": "define",
"D": "def"
} | cs_0057 | multiple_choice | en | Which keyword defines a function? | [
"Python uses def.",
"Others are wrong.",
"Select option D."
] | computer_science | Answer: def.
Steps:
1. Python uses def.
2. Others are wrong.
3. Select option D.
Answer: (D) | python |
Slovník mapuje klíče na hodnoty ve složených závorkách. | null | cs_0058 | concept | cs | Co je slovník (dict)? | [
"Páry klíč: hodnota.",
"Složené závorky.",
"Přístup přes klíč."
] | computer_science | Answer: Mapování klíčů.
Steps:
1. Páry klíč: hodnota.
2. Složené závorky.
3. Přístup přes klíč. | python |
The average is 2.5, from 10 divided by 4. | null | cs_0059 | worked_example | en | What is sum([1,2,3,4])/4? | [
"Sum = 10.",
"Divide by 4.",
"Result = 2.5."
] | computer_science | Answer: 2.5.
Steps:
1. Sum = 10.
2. Divide by 4.
3. Result = 2.5. | python |
'a' in 'cat' is True since 'a' appears in the string. | {
"A": "Error",
"B": "True",
"C": "False",
"D": "None"
} | cs_0060 | multiple_choice | en | What is 'a' in 'cat'? | [
"Check membership.",
"'a' is present.",
"Select option B."
] | computer_science | Answer: True.
Steps:
1. Check membership.
2. 'a' is present.
3. Select option B.
Answer: (B) | python |
let allows reassignment, const forbids it, and var is legacy function-scoped. | null | cs_0061 | concept | en | How do let, const, and var differ? | [
"let: block-scoped, mutable.",
"const: no reassignment.",
"var: legacy, function-scoped."
] | computer_science | Answer: Mutable, fixed, legacy.
Steps:
1. let: block-scoped, mutable.
2. const: no reassignment.
3. var: legacy, function-scoped. | javascript |
const forbids rebinding the variable to a new value. | {
"A": "Allows anything",
"B": "Makes objects frozen",
"C": "Forbids reassignment",
"D": "Deletes variables"
} | cs_0062 | multiple_choice | en | What does const prevent? | [
"Binding stays fixed.",
"Contents may mutate.",
"Select option C."
] | computer_science | Answer: Forbids reassignment.
Steps:
1. Binding stays fixed.
2. Contents may mutate.
3. Select option C.
Answer: (C) | javascript |
map doubles each element, giving [2, 4, 6]. | null | cs_0063 | worked_example | en | What does [1,2,3].map(x => x*2) return? | [
"Apply x*2 to 1: 2.",
"To 2: 4; to 3: 6.",
"Result [2, 4, 6]."
] | computer_science | Answer: [2, 4, 6].
Steps:
1. Apply x*2 to 1: 2.
2. To 2: 4; to 3: 6.
3. Result [2, 4, 6]. | javascript |
Pole je seřazená kolekce prvků v hranatých závorkách. | null | cs_0064 | concept | cs | Co je pole v JavaScriptu? | [
"Hranaté závorky.",
"Indexování od 0.",
"Metody map, filter."
] | computer_science | Answer: Seřazená kolekce.
Steps:
1. Hranaté závorky.
2. Indexování od 0.
3. Metody map, filter. | javascript |
'hello'.length counts 5 characters. | null | cs_0065 | worked_example | en | What is 'hello'.length? | [
"Count h,e,l,l,o.",
"Total 5.",
"length = 5."
] | computer_science | Answer: 5.
Steps:
1. Count h,e,l,l,o.
2. Total 5.
3. length = 5. | javascript |
Strict === compares value and type without coercion. | {
"A": "Value and type",
"B": "Value only",
"C": "Type only",
"D": "Nothing"
} | cs_0066 | multiple_choice | en | What does === check? | [
"No type coercion.",
"Both must match.",
"Select option A."
] | computer_science | Answer: Value and type.
Steps:
1. No type coercion.
2. Both must match.
3. Select option A.
Answer: (A) | javascript |
Arrow functions are compact (x) => expr with lexical this. | null | cs_0067 | concept | en | What are arrow functions? | [
"Short syntax.",
"Lexical this binding.",
"Example: x => x*2."
] | computer_science | Answer: Compact lexical functions.
Steps:
1. Short syntax.
2. Lexical this binding.
3. Example: x => x*2. | javascript |
Filtr vrátí [2, 3], prvky větší než 1. | null | cs_0068 | worked_example | cs | Co vrátí [1,2,3].filter(x => x > 1)? | [
"Testuj 1: ne.",
"Testuj 2, 3: ano.",
"Výsledek [2, 3]."
] | computer_science | Answer: [2, 3].
Steps:
1. Testuj 1: ne.
2. Testuj 2, 3: ano.
3. Výsledek [2, 3]. | javascript |
JSON.parse converts a JSON string into an object. | {
"A": "Object to string",
"B": "Number to string",
"C": "Array to set",
"D": "String to object"
} | cs_0069 | multiple_choice | en | What does JSON.parse do? | [
"Takes JSON text.",
"Builds value.",
"Select option D."
] | computer_science | Answer: String to object.
Steps:
1. Takes JSON text.
2. Builds value.
3. Select option D.
Answer: (D) | javascript |
Promises represent future values with then/catch chains instead of nested callbacks. | null | cs_0070 | concept | en | What are promises? | [
"Pending, then settled.",
"then handles success.",
"catch handles errors."
] | computer_science | Answer: Future values with chains.
Steps:
1. Pending, then settled.
2. then handles success.
3. catch handles errors. | javascript |
2 + '2' coerces to string concatenation, giving '22'. | null | cs_0071 | worked_example | en | What is 2 + '2' in JavaScript? | [
"One operand is string.",
"Number coerces to '2'.",
"Concat gives '22'."
] | computer_science | Answer: '22'.
Steps:
1. One operand is string.
2. Number coerces to '2'.
3. Concat gives '22'. | javascript |
Object literals group key-value pairs in braces. | null | cs_0072 | concept | en | What are object literals? | [
"Braces hold pairs.",
"Keys map to values.",
"Example: {a: 1}."
] | computer_science | Answer: Key-value in braces.
Steps:
1. Braces hold pairs.
2. Keys map to values.
3. Example: {a: 1}. | javascript |
Arrays are objects, so typeof [] is 'object'. | {
"A": "array",
"B": "object",
"C": "list",
"D": "undefined"
} | cs_0073 | multiple_choice | en | What is typeof []? | [
"Arrays inherit objects.",
"typeof reports object.",
"Select option B."
] | computer_science | Answer: 'object'.
Steps:
1. Arrays inherit objects.
2. typeof reports object.
3. Select option B.
Answer: (B) | javascript |
Math.max(3, 7, 5) vrátí 7. | null | cs_0074 | worked_example | cs | Co vrátí Math.max(3, 7, 5)? | [
"Porovnej 3 a 7.",
"Větší je 7.",
"Proti 5 vítězí 7."
] | computer_science | Answer: 7.
Steps:
1. Porovnej 3 a 7.
2. Větší je 7.
3. Proti 5 vítězí 7. | javascript |
Template literals use backticks with ${} interpolation. | null | cs_0075 | concept | en | What are template literals? | [
"Backtick strings.",
"Embed ${expr}.",
"Span multiple lines."
] | computer_science | Answer: Backtick interpolated strings.
Steps:
1. Backtick strings.
2. Embed ${expr}.
3. Span multiple lines. | javascript |
SELECT lists columns from a table, optionally filtered and ordered. | null | cs_0076 | concept | en | What does SELECT do in SQL? | [
"Names columns.",
"Names table.",
"Adds filters."
] | computer_science | Answer: Reads columns from table.
Steps:
1. Names columns.
2. Names table.
3. Adds filters. | sql |
WHERE filters rows by a condition. | {
"A": "WHERE",
"B": "ORDER",
"C": "GROUP",
"D": "JOIN"
} | cs_0077 | multiple_choice | en | Which clause filters rows? | [
"Need row condition.",
"That is WHERE.",
"Select option A."
] | computer_science | Answer: WHERE.
Steps:
1. Need row condition.
2. That is WHERE.
3. Select option A.
Answer: (A) | sql |
SELECT 2 + 3 returns 5. | null | cs_0078 | worked_example | en | What does SELECT 2 + 3 return? | [
"Add 2 and 3.",
"Result 5.",
"One row returned."
] | computer_science | Answer: 5.
Steps:
1. Add 2 and 3.
2. Result 5.
3. One row returned. | sql |
SELECT čte sloupce z tabulky, volitelně s filtrem. | null | cs_0079 | concept | cs | Co je dotaz SELECT? | [
"Jmenuje sloupce.",
"Jmenuje tabulku.",
"Přidá filtr."
] | computer_science | Answer: Čtení z tabulky.
Steps:
1. Jmenuje sloupce.
2. Jmenuje tabulku.
3. Přidá filtr. | sql |
COUNT(*) over 4 rows returns 4. | null | cs_0080 | worked_example | en | Table t has 4 rows. What does SELECT COUNT(*) FROM t return? | [
"Count all rows.",
"Four present.",
"Returns 4."
] | computer_science | Answer: 4.
Steps:
1. Count all rows.
2. Four present.
3. Returns 4. | sql |
ORDER BY sorts result rows by columns. | {
"A": "WHERE",
"B": "GROUP BY",
"C": "ORDER BY",
"D": "HAVING"
} | cs_0081 | multiple_choice | en | Which clause sorts results? | [
"Need ordering.",
"That is ORDER BY.",
"Select option C."
] | computer_science | Answer: ORDER BY.
Steps:
1. Need ordering.
2. That is ORDER BY.
3. Select option C.
Answer: (C) | sql |
INNER keeps matches, LEFT keeps all left rows, FULL keeps everything. | null | cs_0082 | concept | en | How do JOIN types differ? | [
"INNER: matches only.",
"LEFT: all left rows.",
"FULL: all rows both."
] | computer_science | Answer: Match scope differs.
Steps:
1. INNER: matches only.
2. LEFT: all left rows.
3. FULL: all rows both. | sql |
SELECT 10.0 / 4 vrátí 2.5. | null | cs_0083 | worked_example | cs | Co vrátí SELECT 10.0 / 4? | [
"Vyděl 10.0 čtyřmi.",
"Výsledek 2.5.",
"Jeden řádek."
] | computer_science | Answer: 2.5.
Steps:
1. Vyděl 10.0 čtyřmi.
2. Výsledek 2.5.
3. Jeden řádek. | sql |
DISTINCT drops duplicate rows from results. | {
"A": "UNIQUE",
"B": "DISTINCT",
"C": "FILTER",
"D": "LIMIT"
} | cs_0084 | multiple_choice | en | Which keyword removes duplicates? | [
"Need dedup.",
"That is DISTINCT.",
"Select option B."
] | computer_science | Answer: DISTINCT.
Steps:
1. Need dedup.
2. That is DISTINCT.
3. Select option B.
Answer: (B) | sql |
GROUP BY aggregates per group; HAVING filters groups like WHERE filters rows. | null | cs_0085 | concept | en | How do GROUP BY and HAVING work? | [
"Group rows by key.",
"Aggregate each group.",
"HAVING filters groups."
] | computer_science | Answer: Aggregate then filter groups.
Steps:
1. Group rows by key.
2. Aggregate each group.
3. HAVING filters groups. | sql |
SUM(1, 2, 3) totals 6. | null | cs_0086 | worked_example | en | What does SELECT SUM(x) give for x in (1,2,3)? | [
"Add 1 + 2 + 3.",
"Total 6.",
"One row returned."
] | computer_science | Answer: 6.
Steps:
1. Add 1 + 2 + 3.
2. Total 6.
3. One row returned. | sql |
A primary key uniquely identifies each row and cannot be NULL. | null | cs_0087 | concept | en | What is a primary key? | [
"Unique per row.",
"Never NULL.",
"Example: id column."
] | computer_science | Answer: Unique row identifier.
Steps:
1. Unique per row.
2. Never NULL.
3. Example: id column. | sql |
PRIMARY KEY enforces unique non-null row identity. | {
"A": "FOREIGN KEY",
"B": "INDEX",
"C": "NULL",
"D": "PRIMARY KEY"
} | cs_0088 | multiple_choice | en | Which constraint gives unique row identity? | [
"Need unique id.",
"That is PRIMARY KEY.",
"Select option D."
] | computer_science | Answer: PRIMARY KEY.
Steps:
1. Need unique id.
2. That is PRIMARY KEY.
3. Select option D.
Answer: (D) | sql |
Primární klíč jednoznačně určuje každý řádek a není NULL. | null | cs_0089 | concept | cs | Co je primární klíč? | [
"Jedinečný na řádek.",
"Nikdy NULL.",
"Příklad: sloupec id."
] | computer_science | Answer: Jedinečný identifikátor.
Steps:
1. Jedinečný na řádek.
2. Nikdy NULL.
3. Příklad: sloupec id. | sql |
AVG(10, 20, 30) = 60/3 = 20.0. | null | cs_0090 | worked_example | en | What does SELECT AVG(x) give for x in (10,20,30)? | [
"Sum = 60.",
"Count = 3.",
"Average = 20.0."
] | computer_science | Answer: 20.0.
Steps:
1. Sum = 60.
2. Count = 3.
3. Average = 20.0. | sql |
TCP guarantees ordered delivery; UDP is fast but unreliable. | null | cs_0091 | concept | en | How do TCP and UDP differ? | [
"TCP: reliable, ordered.",
"UDP: fast, best-effort.",
"Use: web vs video."
] | computer_science | Answer: Reliable versus fast.
Steps:
1. TCP: reliable, ordered.
2. UDP: fast, best-effort.
3. Use: web vs video. | networking |
TCP retransmits lost packets for reliability. | {
"A": "TCP",
"B": "UDP",
"C": "IP",
"D": "ICMP"
} | cs_0092 | multiple_choice | en | Which protocol is reliable? | [
"Needs retransmission.",
"TCP provides it.",
"Select option A."
] | computer_science | Answer: TCP.
Steps:
1. Needs retransmission.
2. TCP provides it.
3. Select option A.
Answer: (A) | networking |
A /24 network holds 254 usable hosts (2^8 - 2). | null | cs_0093 | worked_example | en | How many usable hosts in 192.168.1.0/24? | [
"Host bits = 32 - 24 = 8.",
"Total = 2^8 = 256.",
"Minus network/broadcast = 254."
] | computer_science | Answer: 254.
Steps:
1. Host bits = 32 - 24 = 8.
2. Total = 2^8 = 256.
3. Minus network/broadcast = 254. | networking |
IP adresa je číselný identifikátor zařízení v síti. | null | cs_0094 | concept | cs | Co je IP adresa? | [
"Číselný identifikátor.",
"IPv4 má 32 bitů.",
"Příklad: 192.168.1.1."
] | computer_science | Answer: Identifikátor zařízení.
Steps:
1. Číselný identifikátor.
2. IPv4 má 32 bitů.
3. Příklad: 192.168.1.1. | networking |
DNS resolves domain names to IP addresses via hierarchical lookup. | null | cs_0095 | concept | en | How does DNS resolution work? | [
"Query resolver.",
"Walk root to TLD to auth.",
"Cache the answer."
] | computer_science | Answer: Names to IPs hierarchically.
Steps:
1. Query resolver.
2. Walk root to TLD to auth.
3. Cache the answer. | networking |
DNS maps domain names to IP addresses. | {
"A": "IPs to MACs",
"B": "Names to IPs",
"C": "Ports to apps",
"D": "Files to URLs"
} | cs_0096 | multiple_choice | en | What does DNS map? | [
"Names in, IPs out.",
"Eliminate others.",
"Select option B."
] | computer_science | Answer: Names to IPs.
Steps:
1. Names in, IPs out.
2. Eliminate others.
3. Select option B.
Answer: (B) | networking |
A /16 holds 65,534 usable hosts (2^16 - 2). | null | cs_0097 | worked_example | en | How many usable hosts in a /16 network? | [
"Host bits = 16.",
"Total = 2^16 = 65,536.",
"Minus 2 = 65,534."
] | computer_science | Answer: 65,534.
Steps:
1. Host bits = 16.
2. Total = 2^16 = 65,536.
3. Minus 2 = 65,534. | networking |
HTTP standardně používá port 80. | null | cs_0098 | worked_example | cs | Kolik je standardní port HTTP? | [
"HTTP má 80.",
"HTTPS má 443.",
"Odpověď: 80."
] | computer_science | Answer: 80.
Steps:
1. HTTP má 80.
2. HTTPS má 443.
3. Odpověď: 80. | networking |
HTTP defaults to port 80. | {
"A": "21",
"B": "25",
"C": "80",
"D": "443"
} | cs_0099 | multiple_choice | en | What is the default HTTP port? | [
"HTTP standard.",
"Port 80.",
"Select option C."
] | computer_science | Answer: 80.
Steps:
1. HTTP standard.
2. Port 80.
3. Select option C.
Answer: (C) | networking |
The OSI model has 7 layers from physical to application. | null | cs_0100 | concept | en | How many OSI layers exist? | [
"Physical to application.",
"Seven total.",
"Example: network is 3."
] | computer_science | Answer: 7 layers.
Steps:
1. Physical to application.
2. Seven total.
3. Example: network is 3. | networking |
A /24 mask is 255.255.255.0: 24 ones then 8 zeros. | null | cs_0101 | worked_example | en | What is the subnet mask for /24? | [
"24 network bits set.",
"Three full octets.",
"Mask = 255.255.255.0."
] | computer_science | Answer: 255.255.255.0.
Steps:
1. 24 network bits set.
2. Three full octets.
3. Mask = 255.255.255.0. | networking |
HTTPS defaults to port 443. | {
"A": "80",
"B": "21",
"C": "25",
"D": "443"
} | cs_0102 | multiple_choice | en | What is the default HTTPS port? | [
"Encrypted HTTP.",
"Port 443.",
"Select option D."
] | computer_science | Answer: 443.
Steps:
1. Encrypted HTTP.
2. Port 443.
3. Select option D.
Answer: (D) | networking |
DNS převádí doménová jména na IP adresy. | null | cs_0103 | concept | cs | Co je DNS? | [
"Jména na adresy.",
"Hierarchické dotazy.",
"Ukládání do mezipaměti."
] | computer_science | Answer: Překlad jmen na IP.
Steps:
1. Jména na adresy.
2. Hierarchické dotazy.
3. Ukládání do mezipaměti. | networking |
Switches forward within a LAN by MAC; routers join networks by IP. | null | cs_0104 | concept | en | How do routers and switches differ? | [
"Switch: LAN, MAC-based.",
"Router: networks, IP-based.",
"Layers 2 vs 3."
] | computer_science | Answer: LAN versus networks.
Steps:
1. Switch: LAN, MAC-based.
2. Router: networks, IP-based.
3. Layers 2 vs 3. | networking |
192.168.1.1 is private; the rest are public addresses. | {
"A": "192.168.1.1",
"B": "8.8.8.8",
"C": "1.1.1.1",
"D": "9.9.9.9"
} | cs_0105 | multiple_choice | en | Which IP is private? | [
"192.168.x is private.",
"Others are public.",
"Select option A."
] | computer_science | Answer: 192.168.1.1.
Steps:
1. 192.168.x is private.
2. Others are public.
3. Select option A.
Answer: (A) | networking |
The relational model stores data in tables of rows and columns. | null | cs_0106 | concept | en | What is the relational model? | [
"Tables hold data.",
"Rows are records.",
"Keys link tables."
] | computer_science | Answer: Tables of rows.
Steps:
1. Tables hold data.
2. Rows are records.
3. Keys link tables. | databases |
Table rows are also called records. | {
"A": "Attributes",
"B": "Records",
"C": "Schemas",
"D": "Keys"
} | cs_0107 | multiple_choice | en | What are table rows also called? | [
"Rows hold one entry.",
"Called records.",
"Select option B."
] | computer_science | Answer: Records.
Steps:
1. Rows hold one entry.
2. Called records.
3. Select option B.
Answer: (B) | databases |
Three INSERTs into an empty table leave 3 rows. | null | cs_0108 | worked_example | en | INSERT 3 rows into an empty table. How many rows? | [
"Start at 0.",
"Add 3.",
"Total = 3."
] | computer_science | Answer: 3.
Steps:
1. Start at 0.
2. Add 3.
3. Total = 3. | databases |
Relační databáze ukládá data do tabulek propojených klíči. | null | cs_0109 | concept | cs | Co je relační databáze? | [
"Tabulky řádků.",
"Sloupce atributů.",
"Klíče spojují."
] | computer_science | Answer: Tabulky s klíči.
Steps:
1. Tabulky řádků.
2. Sloupce atributů.
3. Klíče spojují. | databases |
Indexes speed lookups by avoiding full table scans. | null | cs_0110 | concept | en | What is a database index? | [
"Sorted lookup aid.",
"Skips full scans.",
"Costs write speed."
] | computer_science | Answer: Fast lookup aid.
Steps:
1. Sorted lookup aid.
2. Skips full scans.
3. Costs write speed. | databases |
Indexes exist to make lookups faster. | {
"A": "Faster lookup",
"B": "Slower reads",
"C": "More storage only",
"D": "No effect"
} | cs_0111 | multiple_choice | en | What is an index for? | [
"Avoid full scans.",
"Speed queries.",
"Select option A."
] | computer_science | Answer: Faster lookup.
Steps:
1. Avoid full scans.
2. Speed queries.
3. Select option A.
Answer: (A) | databases |
A cross join of 3 and 4 rows yields at most 12 rows. | null | cs_0112 | worked_example | en | Cross-join tables of 3 and 4 rows. How many rows max? | [
"Each left pairs each right.",
"Multiply: 3 x 4.",
"Max = 12."
] | computer_science | Answer: 12.
Steps:
1. Each left pairs each right.
2. Multiply: 3 x 4.
3. Max = 12. | databases |
Po smazání 1 ze 3 řádků zbudou 2. | null | cs_0113 | worked_example | cs | Tabulka má 3 řádky, DELETE smaže 1. Kolik zbude? | [
"Začni na 3.",
"Odečti 1.",
"Zbývají 2."
] | computer_science | Answer: 2.
Steps:
1. Začni na 3.
2. Odečti 1.
3. Zbývají 2. | databases |
ACID stands for atomicity, consistency, isolation, durability. | {
"A": "Availability",
"B": "Accuracy",
"C": "Atomicity",
"D": "Audit"
} | cs_0114 | multiple_choice | en | What is the A in ACID? | [
"All-or-nothing.",
"That is atomicity.",
"Select option C."
] | computer_science | Answer: Atomicity.
Steps:
1. All-or-nothing.
2. That is atomicity.
3. Select option C.
Answer: (C) | databases |
A transaction groups statements into one atomic unit. | null | cs_0115 | concept | en | What is a transaction? | [
"Group statements.",
"Commit or rollback.",
"Stays atomic."
] | computer_science | Answer: Atomic statement group.
Steps:
1. Group statements.
2. Commit or rollback.
3. Stays atomic. | databases |
Raising 100 by 10% gives 110. | null | cs_0116 | worked_example | en | UPDATE sets price = price * 1.1 with price 100. New value? | [
"Multiply: 100 x 1.1.",
"Result 110.",
"One row updated."
] | computer_science | Answer: 110.
Steps:
1. Multiply: 100 x 1.1.
2. Result 110.
3. One row updated. | databases |
A foreign key references another table's primary key. | null | cs_0117 | concept | en | What is a foreign key? | [
"Points to other table.",
"Matches its PK.",
"Enforces links."
] | computer_science | Answer: Link to other PK.
Steps:
1. Points to other table.
2. Matches its PK.
3. Enforces links. | databases |
Foreign keys reference another table's primary key. | {
"A": "Own index",
"B": "Another table's PK",
"C": "Any column",
"D": "Nothing"
} | cs_0118 | multiple_choice | en | What does a foreign key reference? | [
"Links tables.",
"Targets PK.",
"Select option B."
] | computer_science | Answer: Another table's PK.
Steps:
1. Links tables.
2. Targets PK.
3. Select option B.
Answer: (B) | databases |
Transakce je atomická skupina příkazů s commitem nebo rollbackem. | null | cs_0119 | concept | cs | Co je transakce? | [
"Skupina příkazů.",
"Commit nebo rollback.",
"Vše nebo nic."
] | computer_science | Answer: Atomická skupina.
Steps:
1. Skupina příkazů.
2. Commit nebo rollback.
3. Vše nebo nic. | databases |
The query returns the 2 matching rows. | null | cs_0120 | worked_example | en | 5 rows exist, WHERE matches 2. How many returned? | [
"Filter 5 rows.",
"Keep 2.",
"Returns 2."
] | computer_science | Answer: 2.
Steps:
1. Filter 5 rows.
2. Keep 2.
3. Returns 2. | databases |
A process owns memory; threads share it while running code. | null | cs_0121 | concept | en | How do processes and threads differ? | [
"Process: own memory.",
"Thread: shared memory.",
"Threads run inside processes."
] | computer_science | Answer: Own versus shared memory.
Steps:
1. Process: own memory.
2. Thread: shared memory.
3. Threads run inside processes. | operating_systems |
A thread is the lightweight unit of execution. | {
"A": "Process",
"B": "Program",
"C": "File",
"D": "Thread"
} | cs_0122 | multiple_choice | en | What is the lightweight execution unit? | [
"Runs code.",
"Shares memory.",
"Select option D."
] | computer_science | Answer: Thread.
Steps:
1. Runs code.
2. Shares memory.
3. Select option D.
Answer: (D) | operating_systems |
4 cores with 2 threads each give 8 logical CPUs. | null | cs_0123 | worked_example | en | 4 cores, 2 threads each. How many logical CPUs? | [
"Multiply: 4 x 2.",
"Result 8.",
"8 logical CPUs."
] | computer_science | Answer: 8.
Steps:
1. Multiply: 4 x 2.
2. Result 8.
3. 8 logical CPUs. | operating_systems |
Proces je běžící program s vlastním paměťovým prostorem. | null | cs_0124 | concept | cs | Co je proces? | [
"Běžící program.",
"Vlastní paměť.",
"Spravuje ho OS."
] | computer_science | Answer: Běžící program.
Steps:
1. Běžící program.
2. Vlastní paměť.
3. Spravuje ho OS. | operating_systems |
Paging splits memory into fixed pages swapped between RAM and disk. | null | cs_0125 | concept | en | What is virtual memory paging? | [
"Fixed-size pages.",
"Swap RAM to disk.",
"Illusion of more RAM."
] | computer_science | Answer: Page swapping illusion.
Steps:
1. Fixed-size pages.
2. Swap RAM to disk.
3. Illusion of more RAM. | operating_systems |
FIFO evicts the oldest loaded page first. | {
"A": "Oldest",
"B": "Newest",
"C": "Random",
"D": "Largest"
} | cs_0126 | multiple_choice | en | Which page does FIFO evict? | [
"First in first out.",
"Oldest leaves.",
"Select option A."
] | computer_science | Answer: Oldest.
Steps:
1. First in first out.
2. Oldest leaves.
3. Select option A.
Answer: (A) | operating_systems |
Three fresh references with 3 frames cause 3 page faults. | null | cs_0127 | worked_example | en | 3 frames empty, references 1, 2, 3. How many faults? | [
"1 misses: fault.",
"2 misses: fault.",
"3 misses: fault; total 3."
] | computer_science | Answer: 3.
Steps:
1. 1 misses: fault.
2. 2 misses: fault.
3. 3 misses: fault; total 3. | operating_systems |
2 GB RAM plus 1 GB swap dá 3 GB virtuální paměti. | null | cs_0128 | worked_example | cs | 2 GB RAM a 1 GB swap. Kolik virtuální paměti? | [
"Sečti RAM a swap.",
"2 + 1.",
"Celkem 3 GB."
] | computer_science | Answer: 3 GB.
Steps:
1. Sečti RAM a swap.
2. 2 + 1.
3. Celkem 3 GB. | operating_systems |
Deadlock needs all four Coffman conditions at once. | {
"A": "2",
"B": "3",
"C": "4",
"D": "1"
} | cs_0129 | multiple_choice | en | How many conditions does deadlock need? | [
"Mutual exclusion etc.",
"Four total.",
"Select option C."
] | computer_science | Answer: 4.
Steps:
1. Mutual exclusion etc.
2. Four total.
3. Select option C.
Answer: (C) | operating_systems |
Round-robin cycles processes with fixed time quanta. | null | cs_0130 | concept | en | How does round-robin scheduling work? | [
"Queue processes.",
"Run each one quantum.",
"Cycle repeats."
] | computer_science | Answer: Cycling time quanta.
Steps:
1. Queue processes.
2. Run each one quantum.
3. Cycle repeats. | operating_systems |
One cycle over 3 processes at 10 ms takes 30 ms. | null | cs_0131 | worked_example | en | Quantum 10 ms, 3 processes. How long is one cycle? | [
"Each runs 10 ms.",
"Three in cycle.",
"Total = 30 ms."
] | computer_science | Answer: 30 ms.
Steps:
1. Each runs 10 ms.
2. Three in cycle.
3. Total = 30 ms. | operating_systems |
Kernel mode runs privileged instructions; user mode cannot. | {
"A": "Slower",
"B": "Privileged",
"C": "Optional",
"D": "Removed"
} | cs_0132 | multiple_choice | en | How is kernel mode best described? | [
"Full hardware access.",
"Privileged level.",
"Select option B."
] | computer_science | Answer: Privileged.
Steps:
1. Full hardware access.
2. Privileged level.
3. Select option B.
Answer: (B) | operating_systems |
Vlákno je lehká jednotka běhu sdílející paměť procesu. | null | cs_0133 | concept | cs | Co je vlákno (thread)? | [
"Běží uvnitř procesu.",
"Sdílí paměť.",
"Vlastní zásobník."
] | computer_science | Answer: Lehká jednotka běhu.
Steps:
1. Běží uvnitř procesu.
2. Sdílí paměť.
3. Vlastní zásobník. | operating_systems |
Inodes store file metadata and block pointers. | null | cs_0134 | concept | en | What is an inode? | [
"Metadata per file.",
"Points to blocks.",
"Name lives in directory."
] | computer_science | Answer: File metadata node.
Steps:
1. Metadata per file.
2. Points to blocks.
3. Name lives in directory. | operating_systems |
A mutex grants one holder at a time, ensuring mutual exclusion. | {
"A": "Mutual exclusion",
"B": "Parallel access",
"C": "No locking",
"D": "Deadlock"
} | cs_0135 | multiple_choice | en | What does a mutex ensure? | [
"One holder only.",
"Others wait.",
"Select option A."
] | computer_science | Answer: Mutual exclusion.
Steps:
1. One holder only.
2. Others wait.
3. Select option A.
Answer: (A) | operating_systems |
A class is a blueprint; objects are its instances. | null | cs_0136 | concept | en | How do classes and objects differ? | [
"Class defines shape.",
"Object holds data.",
"Many objects per class."
] | computer_science | Answer: Blueprint versus instance.
Steps:
1. Class defines shape.
2. Object holds data.
3. Many objects per class. | oop |
The class is the blueprint; objects instantiate it. | {
"A": "Object",
"B": "Class",
"C": "Method",
"D": "Field"
} | cs_0137 | multiple_choice | en | What is the blueprint? | [
"Blueprint defines.",
"That is class.",
"Select option B."
] | computer_science | Answer: Class.
Steps:
1. Blueprint defines.
2. That is class.
3. Select option B.
Answer: (B) | oop |
Two increments raise count from 0 to 2. | null | cs_0138 | worked_example | en | Counter starts at 0, inc() twice. What is count? | [
"Start 0.",
"First inc: 1.",
"Second inc: 2."
] | computer_science | Answer: 2.
Steps:
1. Start 0.
2. First inc: 1.
3. Second inc: 2. | oop |
Třída je předpis, objekt jeho konkrétní instance. | null | cs_0139 | concept | cs | Co je třída a objekt? | [
"Třída definuje tvar.",
"Objekt drží data.",
"Mnoho objektů z třídy."
] | computer_science | Answer: Předpis versus instance.
Steps:
1. Třída definuje tvar.
2. Objekt drží data.
3. Mnoho objektů z třídy. | oop |
Encapsulation bundles data with methods and hides internals. | null | cs_0140 | concept | en | What is encapsulation? | [
"Bundle data, methods.",
"Hide internals.",
"Expose interface."
] | computer_science | Answer: Bundled hidden data.
Steps:
1. Bundle data, methods.
2. Hide internals.
3. Expose interface. | oop |
Encapsulation hides internal details behind an interface. | {
"A": "Encapsulation",
"B": "Inheritance",
"C": "Polymorphism",
"D": "Abstraction"
} | cs_0141 | multiple_choice | en | What hides internal details? | [
"Need hiding.",
"That is encapsulation.",
"Select option A."
] | computer_science | Answer: Encapsulation.
Steps:
1. Need hiding.
2. That is encapsulation.
3. Select option A.
Answer: (A) | oop |
Dog inherits speak and returns 'woof'. | null | cs_0142 | worked_example | en | Dog(Animal) defines speak() as 'woof'. What does Dog().speak() give? | [
"Dog inherits Animal.",
"speak returns 'woof'.",
"Result 'woof'."
] | computer_science | Answer: 'woof'.
Steps:
1. Dog inherits Animal.
2. speak returns 'woof'.
3. Result 'woof'. | oop |
Dědičnost přebírá vlastnosti rodičovské třídy. | null | cs_0143 | concept | cs | Co je dědičnost? | [
"Potomek dědí.",
"Rozšiřuje rodiče.",
"Opakuje méně kódu."
] | computer_science | Answer: Přebírání od rodiče.
Steps:
1. Potomek dědí.
2. Rozšiřuje rodiče.
3. Opakuje méně kódu. | oop |
Polymorphism lets one interface behave differently per type. | {
"A": "Encapsulation",
"B": "Inheritance",
"C": "Polymorphism",
"D": "Coupling"
} | cs_0144 | multiple_choice | en | What gives one interface many behaviors? | [
"Same call, varied act.",
"That is polymorphism.",
"Select option C."
] | computer_science | Answer: Polymorphism.
Steps:
1. Same call, varied act.
2. That is polymorphism.
3. Select option C.
Answer: (C) | oop |
len() calls __len__, returning 3. | null | cs_0145 | worked_example | en | A class defines __len__ returning 3. What is len(obj)? | [
"len calls __len__.",
"Method returns 3.",
"Result 3."
] | computer_science | Answer: 3.
Steps:
1. len calls __len__.
2. Method returns 3.
3. Result 3. | oop |
__init__ initializes new instances with starting state. | null | cs_0146 | concept | en | What is a constructor in Python? | [
"Called at creation.",
"Method __init__.",
"Sets attributes."
] | computer_science | Answer: __init__ initializer.
Steps:
1. Called at creation.
2. Method __init__.
3. Sets attributes. | oop |
Rectangle(3, 4).area() = 3 x 4 = 12. | null | cs_0147 | worked_example | en | Rectangle(3, 4).area() with area = w*h. What value? | [
"Width 3, height 4.",
"Multiply: 12.",
"Result 12."
] | computer_science | Answer: 12.
Steps:
1. Width 3, height 4.
2. Multiply: 12.
3. Result 12. | oop |
self refers to the current instance inside methods. | {
"A": "Class",
"B": "Module",
"C": "Parent",
"D": "Instance"
} | cs_0148 | multiple_choice | en | What does self refer to? | [
"Method context.",
"Current object.",
"Select option D."
] | computer_science | Answer: Instance.
Steps:
1. Method context.
2. Current object.
3. Select option D.
Answer: (D) | oop |
Polymorfismus umožňuje stejné rozhraní s různým chováním. | null | cs_0149 | concept | cs | Co je polymorfismus? | [
"Stejné volání.",
"Různé chování.",
"Podle typu objektu."
] | computer_science | Answer: Jedno rozhraní, více chování.
Steps:
1. Stejné volání.
2. Různé chování.
3. Podle typu objektu. | oop |
Child overrides greet, so it returns 'hi child'. | null | cs_0150 | worked_example | en | Child overrides greet() with 'hi child'. What does Child().greet() give? | [
"Child defines greet.",
"Override wins.",
"Result 'hi child'."
] | computer_science | Answer: 'hi child'.
Steps:
1. Child defines greet.
2. Override wins.
3. Result 'hi child'. | oop |
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