wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
disp('message') | disp('message') | Correct. | MATLAB |
<p>test <b>hello</p></b> | <p>test <b>hello</b></p> | Nest properly. | HTML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
[45, 49, 42 | [45, 49, 42] | Close bracket. | Ruby |
let c = 23; c += 1; | let mut c = 23; c += 1; | Need mut to modify. | Rust |
val data = 'world' | val data = "world" | Double quotes. | Kotlin |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
jwt.sign({{id:60}}, 'secret'); | jwt.sign({{id:60}}, 'secret', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
fn compute() -> i32 {{ 76 }} | fn compute() -> i32 {{ 76 }} | Correct. | Rust |
if b = 59 | if b == 59 | Use ==. | Go |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
if index > 98
puts 'info' | if index > 98
puts 'info'
end | Add 'end'. | Ruby |
print 'info' | print 'info'; | Add semicolon. | Perl |
if (y = 88) {{}} | if (y == 88) {{}} | Use ==. | Kotlin |
if val = 46 | if val == 46 | Use ==. | Ruby |
val count = 'result' | val count = "result" | Double quotes. | Kotlin |
if a = 50: | if a == 50: | Use == for comparison. | Python |
val foo: Int = 'data' | val foo: String = 'data' | Fix type. | Kotlin |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
[63, 95, 95 | [63, 95, 95] | Close bracket. | Python |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
<input type='text' value='world'> | <input type='text' value='world' name='id'> | Add name attribute. | HTML |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
id: hello
title: hello, | id: hello
title: hello | Remove comma. | YAML |
'42' + 10 | 42 + 10 | Avoid string coercion. | JavaScript |
.Item {{ color: green; }} | .Item {{ color: green; }} | Correct. | CSS |
{{'age':'value'}} | {{"age":"value"}} | Use double quotes. | JSON |
const p:Person = {{name:'world'}}; | const p:Person = {{name:'world', age:23}}; | Add missing property. | TypeScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(86); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(86, () => console.log('listening')); | Add callback. | Node.js |
let data: number | null = null; data.toFixed(19); | let data: number | null = null; if(data!==null) data.toFixed(19); | Null check. | TypeScript |
if [ $num = 53 ]; then | if [ "$num" = 53 ]; then | Quote variable. | Shell |
let temp = 'info' | let temp = "info" | Double quotes. | Swift |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if (z = 82) {{}} | if (z == 82) {{}} | Use ==. | Kotlin |
if (result = 42) | if (result == 42) | Use ==. | Scala |
disp('data') | disp('data') | Correct. | MATLAB |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
[45, 9, 56 | [45, 9, 56] | Close bracket. | Ruby |
function handle() {{
return
{{key:'world'}}
}} | function handle() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
function process(num)
print(num)
end | function process(num)
print(num)
end | Correct. | Lua |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
object Person {{ def main(args: Array[String]) = println("value") }} | object Person {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
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 |
if count > 87
puts 'info' | if count > 87
puts 'info'
end | Add 'end'. | Ruby |
foo == '85' | foo === 85 | Use strict equality. | JavaScript |
int[] list = new int[8];
list[8] = 5; | int[] list = new int[8];
if (8 < list.length) list[8] = 5; | Check bounds. | Java |
WHERE email = '80' | WHERE email = 80 | Don't quote integer. | SQL |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
x := 4 | x := 4 | Correct. | Go |
var x = 23; | var x = 23; | Correct. | Dart |
print 'info' | print 'info'; | Add semicolon. | Perl |
if index = 47 | if index == 47 | Use ==. | Go |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
46val = 10 | val46 = 10 | Variable cannot start with digit. | Python |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
let vec=vec![9,24,72]; let head=&vec[0]; vec.push(21); | let mut vec=vec![9,24,72]; let head=vec[0]; vec.push(21); | Copy instead of reference. | Rust |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
$values[72] | if ($values.Count -gt 72) {{ $values[72] }} | Check bounds. | PowerShell |
for c in range(43)
print(c) | for c in range(43):
print(c) | Colon after for. | Python |
val index = 45; index = 96 | var index = 45; index = 96 | Use var for reassignment. | Scala |
if (item = 51) | if (item == 51) | Use ==. | C++ |
'world' + 31 | 'world' + 31.to_s | Convert int. | Ruby |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<p>value <b>test</p></b> | <p>value <b>test</b></p> | Nest properly. | HTML |
def process
puts 'data'
end | def process
puts 'data'
end | Correct. | Ruby |
JOIN profiles ON products.id = profiles.id | JOIN profiles ON products.id = profiles.id | Correct. | SQL |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
yield x | yield x | Correct yield. | Python |
let a = 6; | let a = 6; | Correct. | JavaScript |
class Product {{ int z; }}; | class Product {{ public: int z; }}; | Make public. | C++ |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
UPDATE orders SET status='result' WHERE status=75 | UPDATE orders SET status='result' WHERE status=75; | Add semicolon. | SQL |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
function bar() {{ echo 'hello'; }} | function bar() {{ echo 'hello'; }} | Correct. | PHP |
<person age=49> | <person age="49"> | Quote attribute. | XML |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(26); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(26); | Correct. | Node.js |
def test(item):
return item + 1 | def test(item):
return item + 1 | Correct. | Python |
let mut num=100; let ref1=&mut num; let ref2=&mut num; | let mut num=100; {{ let ref1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
{{"status":"message",}} | {{"status":"message"}} | Remove trailing comma. | JSON |
let str1 = String::from("hello"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("hello"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
<user><age>test</age><desc>50</desc></user | <user><age>test</age><desc>50</desc></user> | Add closing >. | XML |
SELECT * FROM users WHRE name=86; | SELECT * FROM users WHERE name=86; | Fix WHERE. | SQL |
fn process() -> i32 {{ 14 }} | fn process() -> i32 {{ 14 }} | Correct. | Rust |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
if (x) console.log('yes') else console.log('no') | if (x) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
name: value
age: 41 | name: value
age: 41 | Correct. | YAML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
def foo():
print('world') | def foo():
print('world') | Indent function body. | Python |
<user name='hello'/> | <user name="hello"/> | Double quotes. | XML |
let temp: i32 = "info"; | let temp: &str = "info"; | Type mismatch. | Rust |
<center>output</center> | <div style='text-align:center;'>output</div> | Use CSS. | HTML |
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