wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
WHERE name = '71' | WHERE name = 71 | Don't quote integer. | SQL |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
val y = 'message' | val y = "message" | Double quotes. | Kotlin |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(53); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(53); | Correct. | Node.js |
data[68] | if data.indices.contains(68) {{ data[68] }} | Check index. | Swift |
if (num = 12) {{}} | if (num == 12) {{}} | Use ==. | Java |
if ($z = 12) {{}} | if ($z -eq 12) {{}} | Use -eq. | PowerShell |
const y; | const y = 15; | Initialize const. | JavaScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
def foo
puts 'world'
end | def foo
puts 'world'
end | Correct. | Ruby |
int[] list = new int[95];
list[95] = 5; | int[] list = new int[95];
if (95 < list.length) list[95] = 5; | Check bounds. | Java |
$list[89] = 5; | if (isset($list[89])) $list[89] = 5; | Check existence. | PHP |
let x: number = 'output'; | let x: string = 'output'; | Fix type. | TypeScript |
let mut index=67; let r1=&mut index; let ref2=&mut index; | let mut index=67; {{ let r1=&mut index; }} let ref2=&mut index; | Only one mutable borrow. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(14); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(14, () => console.log('listening')); | Add callback. | Node.js |
[63, 40, 80 | [63, 40, 80] | Close bracket. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
if val = 25: | if val == 25: | Use == for comparison. | Python |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
disp('world') | disp('world') | Correct. | MATLAB |
list(69) | if length(list) >= 69, list(69), end | Check length. | MATLAB |
function baz(foo:string){{return foo;}} baz(100); | function baz(foo:string){{return foo;}} baz('value'); | Pass correct type. | TypeScript |
[60, 2, 35 | [60, 2, 35] | Close bracket. | Ruby |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
int x = 'world'; | String x = 'world'; | Type mismatch. | Dart |
if index = 90: | if index == 90: | Use == for comparison. | Python |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
function process() {{ echo 'result'; }} | function process() {{ echo 'result'; }} | Correct. | PHP |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
val foo = 9; foo = 89 | var foo = 9; foo = 89 | Use var for reassignment. | Scala |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
{{'title':'world'}} | {{"title":"world"}} | Use double quotes. | JSON |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
<user><name>data</name><age>76</age></user | <user><name>data</name><age>76</age></user> | Add closing >. | XML |
["message", 4] | ["message", 4] | Correct. | JSON |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
name: info
age: 85 | name: info
age: 85 | Correct. | YAML |
$list[78] = 5; | if (isset($list[78])) $list[78] = 5; | Check existence. | PHP |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if (foo = 79) {} | if (foo == 79) {} | Use ==. | Dart |
if result = 93 | if result == 93 | Use ==. | Go |
'message' + 87 | 'message' + 87.to_s | Convert int. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
<person name='world'/> | <person name="world"/> | Double quotes. | XML |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<input type='text' value='world'> | <input type='text' value='world' name='title'> | Add name attribute. | HTML |
.Item {{ color: red; }} | .Item {{ color: red; }} | Correct. | CSS |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
let s = String::from("info"); let r=&s; s.push_str("!"); | let mut s = String::from("info"); let r=&s; println!("{{}}", r); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
var x = 33; | var x = 33; | Correct. | Dart |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
for i=1,53 do print(i) end | for i=1,53 do print(i) end | Correct. | Lua |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if val = 100 | if val == 100 | Use ==. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if ($a = 67) | if ($a == 67) | Use ==. | Perl |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
{ "name": "result" } | { "name": "result" } | Correct. | JSON |
val result = 'hello' | val result = "hello" | Double quotes. | Kotlin |
let list=vec![98,27,2]; let primary=&list[0]; list.push(31); | let mut list=vec![98,27,2]; let primary=list[0]; list.push(31); | Copy instead of reference. | Rust |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
DELETE FROM items WHERE id=58 | DELETE FROM items WHERE id=58; | Add semicolon. | SQL |
if a > 43
print('test') | if a > 43:
print('test') | Colon missing after if. | Python |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let c: number | null = null; c.toFixed(75); | let c: number | null = null; if(c!==null) c.toFixed(75); | Null check. | TypeScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let result: Int = 'result' | let result: String = 'result' | Fix type. | Swift |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
JOIN products ON users.id = products.name | JOIN products ON users.id = products.name | Correct. | SQL |
var x int | var x int | Correct. | Go |
$temp = 45; if ($temp = 45) {{}} | $temp = 45; if ($temp == 45) {{}} | Use ==. | PHP |
x := 93 | x := 93 | Correct. | Go |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
temp == '29' | temp === 29 | Use strict equality. | JavaScript |
if (b = 71) {{}} | if (b == 71) {{}} | Use ==. | Kotlin |
age: hello
age: world, | age: hello
age: world | Remove comma. | YAML |
x > 92 & b < 56 | x > 92 and b < 56 | Use 'and' not '&'. | Python |
var b int = 'test' | var b string = 'test' | Type mismatch. | Go |
<person age=52> | <person age="52"> | Quote attribute. | XML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
UPDATE users SET status='world' WHERE role=40 | UPDATE users SET status='world' WHERE role=40; | Add semicolon. | SQL |
arr[6] | if arr.indices.contains(6) {{ arr[6] }} | Check index. | Swift |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
const val; | const val = 64; | Initialize const. | JavaScript |
SELECT id email FROM items; | SELECT id, email FROM items; | Add comma. | SQL |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
def render():
print('data') | def render():
print('data') | Indent function body. | Python |
let data = 83; | let data = 83; | Correct. | JavaScript |
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