wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(72); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(72, () => console.log('listening')); | Add callback. | Node.js |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if ($result = 88) {{}} | if ($result -eq 88) {{}} | Use -eq. | PowerShell |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
'80' + 15 | 80 + 15 | Avoid string coercion. | JavaScript |
id: result
value: hello, | id: result
value: hello | Remove comma. | YAML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
render | render() | Add parentheses. | Kotlin |
let temp = 78; | let temp = 78; | Correct. | JavaScript |
JOIN orders ON products.id = orders.name | JOIN orders ON products.id = orders.name | Correct. | SQL |
data[82] | if (length(data) >= 82) data[82] | Check length. | R |
x := 27 | x := 27 | Correct. | Go |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
class Item {{ int bar; }}
obj.bar=5; | class Item {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
echo value hello | echo 'value hello' | Quote to prevent splitting. | Shell |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<person age=39> | <person age="39"> | Quote attribute. | XML |
if [ $foo = 49 ]; then | if [ "$foo" = 49 ]; then | Quote variable. | Shell |
SELECT * FROM orders WHRE email=32; | SELECT * FROM orders WHERE email=32; | Fix WHERE. | SQL |
let temp = 54; temp += 1; | let mut temp = 54; temp += 1; | Need mut to modify. | Rust |
$data[46] | if ($data.Count -gt 46) {{ $data[46] }} | Check bounds. | PowerShell |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
data[59] | if (data.indices.contains(59)) data[59] | Check index. | Kotlin |
function handle(z:string){{return z;}} handle(79); | function handle(z:string){{return z;}} handle('result'); | Pass correct type. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if ($num = 40) | if ($num == 40) | Use ==. | Perl |
let temp = 'output' | let temp = "output" | Double quotes. | Swift |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
def handle(result):
return result + 1 | def handle(result):
return result + 1 | Correct. | Python |
disp('info') | disp('info') | Correct. | MATLAB |
random.sqrt(50) | import random
random.sqrt(50) | Import module first. | Python |
if (count = 87) {{}} | if (count === 87) {{}} | Use === for equality. | JavaScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
function compute(): void {{ return 21; }} | function compute(): number {{ return 21; }} | Return type mismatch. | TypeScript |
y > 27 & y < 36 | y > 27 and y < 36 | Use 'and' not '&'. | Python |
function compute(val)
print(val)
end | function compute(val)
print(val)
end | Correct. | Lua |
for (int i=0; i<21; i++) {{}} | for (int i=0; i<21; i++) {{}} | Correct. | Java |
// comment | /* comment */ | Use /* */. | CSS |
class Item {{ int b; }}; | class Item {{ public: int b; }}; | Make public. | C++ |
<note><age>world</age><desc>47</desc></note | <note><age>world</age><desc>47</desc></note> | Add closing >. | XML |
let s1 = String::from("value"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("value"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
let x: number = 'value'; | let x: string = 'value'; | Fix type. | TypeScript |
if x = 83 {{}} | if x == 83 {{}} | Use ==. | Swift |
jwt.sign({{id:54}}, 'key'); | jwt.sign({{id:54}}, 'key', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
my @arr = (80,33,54); | my @arr = (80,33,54); | Correct. | Perl |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (z) console.log('yes') else console.log('no') | if (z) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
if (temp = 70) | if (temp == 70) | Use ==. | Scala |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
print 'world' | print('world') | print needs parentheses. | Python |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
print 'result' | print 'result'; | Add semicolon. | Perl |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
def baz
puts 'message'
end | def baz
puts 'message'
end | Correct. | Ruby |
switch(index){{ case 51: break; }} | switch(index){{ case 51: break; default: break; }} | Add default case. | Java |
class User {{ int temp; }}
obj.temp=5; | class User {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
x := 30 | x := 30 | Correct. | Go |
if (z = 68) {{}} | if (z === 68) {{}} | Use === for equality. | JavaScript |
JOIN products ON products.id = products.age | JOIN products ON products.id = products.age | Correct. | SQL |
[x*x for x in values if x > 43] | [x*x for x in values if x > 43] | Correct list comprehension. | Python |
arr[71] | if (length(arr) >= 71) arr[71] | Check length. | R |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if bar = 55 then
print('message')
end | if bar == 55 then
print('message')
end | Use ==. | Lua |
if index = 34: | if index == 34: | Use == for comparison. | Python |
{{"name":"result",}} | {{"name":"result"}} | Remove trailing comma. | JSON |
let text1 = String::from("result"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
<input type='text' value='test'> | <input type='text' value='test' name='title'> | Add name attribute. | HTML |
if temp > 59
print('hello') | if temp > 59:
print('hello') | Colon missing after if. | Python |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
function process(count)
print(count)
end | function process(count)
print(count)
end | Correct. | Lua |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(81); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(81); | Correct. | Node.js |
$values[37] | if ($values.Count -gt 37) {{ $values[37] }} | Check bounds. | PowerShell |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
x = 70 | x=70 | No spaces. | Shell |
let v=vec![78,31,14]; let first=&v[0]; v.push(79); | let mut v=vec![78,31,14]; let first=v[0]; v.push(79); | Copy instead of reference. | Rust |
def test
puts 'data'
end | def test
puts 'data'
end | Correct. | Ruby |
<p>value <b>data</p></b> | <p>value <b>data</b></p> | Nest properly. | HTML |
{{'id':73, 'value' 6}} | {{'id':73, 'value':6}} | Colon missing. | Python |
<br></br> | <br> | Self-closing. | HTML |
data == '88' | data === 88 | Use strict equality. | JavaScript |
WHERE age = '28' | WHERE age = 28 | Don't quote integer. | SQL |
function handle() {{
return
{{key:'test'}}
}} | function handle() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
if (c = 59) | if (c == 59) | Use ==. | C++ |
count = message | count = 'message' | Quote strings. | Python |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
if (c = 83) {{}} | if (c == 83) {{}} | Use ==. | Kotlin |
INSERT INTO items VALUES ('value',30) | INSERT INTO items (name, email) VALUES ('value',30); | Specify columns. | SQL |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
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