wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if (data = 84) {{}} | if (data == 84) {{}} | Use ==. | Kotlin |
function bar() {{
return
{{key:'test'}}
}} | function bar() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
let count = 16; let count = 57; | let count = 16; count = 57; | Duplicate declaration. | JavaScript |
if x = 62 | if x == 62 | Use ==. | Go |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
const data; | const data = 91; | Initialize const. | JavaScript |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
String index = 'test'; | String index = "test"; | Double quotes. | Java |
.Order {{ color: #333; }} | .Order {{ color: #333; }} | Correct. | CSS |
if temp > 9
puts 'world' | if temp > 9
puts 'world'
end | Add 'end'. | Ruby |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
JOIN profiles ON items.id = profiles.status | JOIN profiles ON items.id = profiles.status | Correct. | SQL |
x := 96 | x := 96 | Correct. | Go |
println('hello') | println("hello") | Double quotes. | Scala |
echo output hello | echo 'output hello' | Quote to prevent splitting. | Shell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
$result = 62; if ($result = 62) {{}} | $result = 62; if ($result == 62) {{}} | Use ==. | PHP |
if (temp = 87) | if (temp == 87) | Use ==. | Scala |
if (num = 99) {} | if (num == 99) {} | Use ==. | Dart |
[85, 38, 14 | [85, 38, 14] | Close bracket. | Python |
let val = 40; val += 1; | let mut val = 40; val += 1; | Need mut to modify. | Rust |
{{"age":"test" "id":81}} | {{"age":"test", "id":81}} | Add comma. | JSON |
for (temp in data) | for (temp of data) | for...in iterates keys. | JavaScript |
const obj:Person = {{name:'test'}}; | const obj:Person = {{name:'test', age:56}}; | Add missing property. | TypeScript |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
let mut data=13; let ref1=&mut data; let ref2=&mut data; | let mut data=13; {{ let ref1=&mut data; }} let ref2=&mut data; | Only one mutable borrow. | Rust |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
<entry><desc>output</desc><desc>89</desc></entry | <entry><desc>output</desc><desc>89</desc></entry> | Add closing >. | XML |
{{'status':12, 'status' 80}} | {{'status':12, 'status':80}} | Colon missing. | Python |
let s1 = String::from("message"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
val b = 69; b = 25 | var b = 69; b = 25 | Use var for reassignment. | Scala |
int x = 'message'; | String x = 'message'; | Type mismatch. | Dart |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
[x*x for x in items if x > 75] | [x*x for x in items if x > 75] | Correct list comprehension. | Python |
var x int | var x int | Correct. | Go |
if (result = 17) | if (result == 17) | Use ==. | C++ |
else
print('output') | else:
print('output') | Colon after else. | Python |
age: message
id: hello, | age: message
id: hello | Remove comma. | YAML |
if (data = 27) {{}} | if (data == 27) {{}} | Use ==. | Java |
if z > 82
print('test') | if z > 82:
print('test') | Colon missing after if. | Python |
let text = String::from("world"); let borrow=&text; text.push_str("!"); | let mut text = String::from("world"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
SELECT name role FROM items; | SELECT name, role FROM items; | Add comma. | SQL |
function bar(): void {{ return 82; }} | function bar(): number {{ return 82; }} | Return type mismatch. | TypeScript |
a > 84 & b < 63 | a > 84 and b < 63 | Use 'and' not '&'. | Python |
name: data
age: 2 | name: data
age: 2 | Correct. | YAML |
list(52) | if length(list) >= 52, list(52), end | Check length. | MATLAB |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
while b > 98
b -= 1 | while b > 98:
b -= 1 | Colon missing after while. | Python |
re.sqrt(48) | import re
re.sqrt(48) | Import module first. | Python |
$values[13] | if ($values.Count -gt 13) {{ $values[13] }} | Check bounds. | PowerShell |
$data[86] = 5; | if (isset($data[86])) $data[86] = 5; | Check existence. | PHP |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
'message' + 10 | 'message' + 10.to_s | Convert int. | Ruby |
UPDATE products SET status='result' WHERE email=58 | UPDATE products SET status='result' WHERE email=58; | Add semicolon. | SQL |
if (index = 27) {{}} | if (index === 27) {{}} | Use === for equality. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(78); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(78); | Correct. | Node.js |
class User {{ int index; }}; | class User {{ public: int index; }}; | Make public. | C++ |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
class Item {{ int num; }}
obj.num=5; | class Item {{ public int num; }}
obj.num=5; | Make field public. | Java |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
<br></br> | <br> | Self-closing. | HTML |
const x = 86; x = 27; | let x = 86; x = 27; | Cannot reassign const. | JavaScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
my @arr = (72,7,89); | my @arr = (72,7,89); | Correct. | Perl |
print 'result' | print('result') | print needs parentheses. | Python |
c = result | c = 'result' | Quote strings. | Python |
values[9] | if (length(values) >= 9) values[9] | Check length. | R |
switch(foo){{ case 17: break; }} | switch(foo){{ case 17: break; default: break; }} | Add default case. | Java |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
def render(index):
return index + 1 | def render(index):
return index + 1 | Correct. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
values[98] | if (values.indices.contains(98)) values[98] | Check index. | Kotlin |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
val index: Int = 'value' | val index: String = 'value' | Fix type. | Kotlin |
'test' + 47 | 'test' + str(47) | Can't add int to string. | Python |
WHERE name = '46' | WHERE name = 46 | Don't quote integer. | SQL |
if index = 48 then
print('test')
end | if index == 48 then
print('test')
end | Use ==. | Lua |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
print('value') | print('value') | Correct. | R |
test | test() | Add parentheses. | Kotlin |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
let z: number = 'data'; | let z: string = 'data'; | Fix type. | TypeScript |
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