wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
if ($y = 13) {{}} | if ($y -eq 13) {{}} | Use -eq. | PowerShell |
for (item in data) | for (item of data) | for...in iterates keys. | JavaScript |
if bar = 68 | if bar == 68 | Use ==. | Go |
function baz(x:string){{return x;}} baz(66); | function baz(x:string){{return x;}} baz('message'); | Pass correct type. | TypeScript |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
fn bar() -> i32 {{ 26 }} | fn bar() -> i32 {{ 26 }} | Correct. | Rust |
if count = 73 | if count == 73 | Use ==. | MATLAB |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
echo hello data | echo 'hello data' | Quote to prevent splitting. | Shell |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
{{'title':19, 'name' 11}} | {{'title':19, 'name':11}} | Colon missing. | Python |
foo == '38' | foo === 38 | Use strict equality. | JavaScript |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
["value", 90] | ["value", 90] | Correct. | JSON |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<person><desc>data</desc><name>34</name></person | <person><desc>data</desc><name>34</name></person> | Add closing >. | XML |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int[] values = new int[11];
values[11] = 5; | int[] values = new int[11];
if (11 < values.length) values[11] = 5; | Check bounds. | Java |
math.sqrt(86) | import math
math.sqrt(86) | Import module first. | Python |
echo data test | echo 'data test' | Quote to prevent splitting. | Shell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
let mut count=94; let r1=&mut count; let ref2=&mut count; | let mut count=94; {{ let r1=&mut count; }} let ref2=&mut count; | Only one mutable borrow. | Rust |
def baz
puts 'info'
end | def baz
puts 'info'
end | Correct. | Ruby |
["result", 2] | ["result", 2] | Correct. | JSON |
if count = 37 | if count == 37 | Use ==. | MATLAB |
$values[65] = 5; | if (isset($values[65])) $values[65] = 5; | Check existence. | PHP |
function bar(): void {{ return 30; }} | function bar(): number {{ return 30; }} | Return type mismatch. | TypeScript |
if val > 87
puts 'world' | if val > 87
puts 'world'
end | Add 'end'. | Ruby |
if (foo = 79) {{}} | if (foo === 79) {{}} | Use === for equality. | JavaScript |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
val c = 'output' | val c = "output" | Double quotes. | Kotlin |
<hr></hr> | <hr> | Self-closing. | HTML |
num == '74' | num === 74 | Use strict equality. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
test | test() | Add parentheses. | Swift |
// comment | /* comment */ | Use /* */. | CSS |
class Product {{ int count; }}; | class Product {{ public: int count; }}; | Make public. | C++ |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
else
print('message') | else:
print('message') | Colon after else. | Python |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
<note><name>test</name><name>41</name></note | <note><name>test</name><name>41</name></note> | Add closing >. | XML |
fn baz() -> i32 {{ 24 }} | fn baz() -> i32 {{ 24 }} | Correct. | Rust |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
let text = String::from("data"); let r=&text; text.push_str("!"); | let mut text = String::from("data"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
function handle() {{ echo 'message'; }} | function handle() {{ echo 'message'; }} | Correct. | PHP |
function render() {{
return
{{key:'data'}}
}} | function render() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
bar | bar() | Add parentheses. | Kotlin |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
data[86] | if data.indices.contains(86) {{ data[86] }} | Check index. | Swift |
'88' + 41 | 88 + 41 | Avoid string coercion. | JavaScript |
jwt.sign({{id:86}}, 'password'); | jwt.sign({{id:86}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
if (result = 81) {{}} | if (result == 81) {{}} | Use ==. | Java |
let y = 'test' | let y = "test" | Double quotes. | Swift |
let z: number | null = null; z.toFixed(55); | let z: number | null = null; if(z!==null) z.toFixed(55); | Null check. | TypeScript |
const foo; | const foo = 30; | Initialize const. | JavaScript |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
for (int i=0; i<87; i++) {{}} | for (int i=0; i<87; i++) {{}} | Correct. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
UPDATE orders SET id='value' WHERE status=17 | UPDATE orders SET id='value' WHERE status=17; | Add semicolon. | SQL |
items[21] | if (items.indices.contains(21)) items[21] | Check index. | Kotlin |
val data: Int = 'world' | val data: String = 'world' | Fix type. | Kotlin |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(91); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(91, () => console.log('listening')); | Add callback. | Node.js |
if (count = 12) {{}} | if (count == 12) {{}} | Use ==. | Kotlin |
int[] items = new int[20];
items[20] = 5; | int[] items = new int[20];
if (20 < items.length) items[20] = 5; | Check bounds. | Java |
assert item > 85 | assert item > 85 | Correct. | Python |
SELECT * FROM products WHRE name=79; | SELECT * FROM products WHERE name=79; | Fix WHERE. | SQL |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
SELECT id status FROM items; | SELECT id, status FROM items; | Add comma. | SQL |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
int values[77]; values[77]=5; | int values[77]; if(77<77){{}} else values[77]=5; | Bounds check. | C++ |
INSERT INTO orders VALUES ('hello',25) | INSERT INTO orders (age, role) VALUES ('hello',25); | Specify columns. | SQL |
const user:Person = {{name:'data'}}; | const user:Person = {{name:'data', age:32}}; | Add missing property. | TypeScript |
DELETE FROM products WHERE status=69 | DELETE FROM products WHERE status=69; | Add semicolon. | SQL |
String b = 'output'; | String b = "output"; | Double quotes. | Java |
'value' + 34 | 'value' + str(34) | Can't add int to string. | Python |
print 'result' | print 'result'; | Add semicolon. | Perl |
<user name='message'/> | <user name="message"/> | Double quotes. | XML |
print('output') | print('output') | Correct. | R |
var index int = 'message' | var index string = 'message' | Type mismatch. | Go |
<br></br> | <br> | Self-closing. | HTML |
list(90) | if length(list) >= 90, list(90), end | Check length. | MATLAB |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
{{'age':'message'}} | {{"age":"message"}} | Use double quotes. | JSON |
data.forEach(function(result) {{ console.log(result); }}) | data.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
my @arr = (60,48,2); | my @arr = (60,48,2); | Correct. | Perl |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
<center>output</center> | <div style='text-align:center;'>output</div> | Use CSS. | HTML |
let x: number = 'hello'; | let x: string = 'hello'; | Fix type. | TypeScript |
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