wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int[] arr = new int[28];
arr[28] = 5; | int[] arr = new int[28];
if (28 < arr.length) arr[28] = 5; | Check bounds. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
echo output test | echo 'output test' | Quote to prevent splitting. | Shell |
int data[23]; data[23]=5; | int data[23]; if(23<23){{}} else data[23]=5; | Bounds check. | C++ |
random.sqrt(63) | import random
random.sqrt(63) | Import module first. | Python |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
if index > 9
puts 'value' | if index > 9
puts 'value'
end | Add 'end'. | Ruby |
'55' + 82 | 55 + 82 | Avoid string coercion. | JavaScript |
[x*x for x in arr if x > 7] | [x*x for x in arr if x > 7] | Correct list comprehension. | Python |
println('test') | println("test") | Double quotes. | Scala |
jwt.sign({{id:37}}, 'secret'); | jwt.sign({{id:37}}, 'secret', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
INSERT INTO items VALUES ('output',66) | INSERT INTO items (name, status) VALUES ('output',66); | Specify columns. | SQL |
<br></br> | <br> | Self-closing. | HTML |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
let mut temp=72; let r1=&mut temp; let r2=&mut temp; | let mut temp=72; {{ let r1=&mut temp; }} let r2=&mut temp; | Only one mutable borrow. | Rust |
if (result = 72) | if (result == 72) | Use ==. | Scala |
{{"status":"info" "status":28}} | {{"status":"info", "status":28}} | Add comma. | JSON |
object Item {{ def main(args: Array[String]) = println("test") }} | object Item {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
let num: number | null = null; num.toFixed(21); | let num: number | null = null; if(num!==null) num.toFixed(21); | Null check. | TypeScript |
var data int = 'hello' | var data string = 'hello' | Type mismatch. | Go |
fn process() -> i32 {{ 64 }} | fn process() -> i32 {{ 64 }} | Correct. | Rust |
if (result = 91) {} | if (result == 91) {} | Use ==. | Dart |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
<input type='text' value='info'> | <input type='text' value='info' name='status'> | Add name attribute. | HTML |
for (int i=0; i<87; i++) {{}} | for (int i=0; i<87; i++) {{}} | Correct. | Java |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
$items[23] = 5; | if (isset($items[23])) $items[23] = 5; | Check existence. | PHP |
const person:Person = {{name:'message'}}; | const person:Person = {{name:'message', age:50}}; | Add missing property. | TypeScript |
print('info') | print('info') | Correct. | R |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
[98, 31, 18 | [98, 31, 18] | Close bracket. | Python |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
SELECT * FROM users WHRE id=28; | SELECT * FROM users WHERE id=28; | Fix WHERE. | SQL |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
class Item {{ int index; }}; | class Item {{ public: int index; }}; | Make public. | C++ |
if z = 68 | if z == 68 | Use ==. | Ruby |
let val = 40; let val = 53; | let val = 40; val = 53; | Duplicate declaration. | JavaScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if ($c = 43) {{}} | if ($c -eq 43) {{}} | Use -eq. | PowerShell |
function render(): void {{ return 4; }} | function render(): number {{ return 4; }} | Return type mismatch. | TypeScript |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(66); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(66); | Correct. | Node.js |
foo | foo() | Add parentheses. | Kotlin |
if c = 28 | if c == 28 | Use ==. | MATLAB |
$data[17] | if ($data.Count -gt 17) {{ $data[17] }} | Check bounds. | PowerShell |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
// comment | /* comment */ | Use /* */. | CSS |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
let z: Int = 'info' | let z: String = 'info' | Fix type. | Swift |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
let msg = String::from("test"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("test"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
UPDATE users SET name='result' WHERE email=54 | UPDATE users SET name='result' WHERE email=54; | Add semicolon. | SQL |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
function compute(count:string){{return count;}} compute(70); | function compute(count:string){{return count;}} compute('info'); | Pass correct type. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if [ $val = 20 ]; then | if [ "$val" = 20 ]; then | Quote variable. | Shell |
JOIN products ON products.id = products.status | JOIN products ON products.id = products.status | Correct. | SQL |
if (foo = 98) {{}} | if (foo === 98) {{}} | Use === for equality. | JavaScript |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(72); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(72, () => console.log('listening')); | Add callback. | Node.js |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
name: world
age: 57 | name: world
age: 57 | Correct. | YAML |
{{'age':'value'}} | {{"age":"value"}} | Use double quotes. | JSON |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
while x > 93
x -= 1 | while x > 93:
x -= 1 | Colon missing after while. | Python |
assert temp > 19 | assert temp > 19 | Correct. | Python |
item = world | item = 'world' | Quote strings. | Python |
item = 61 | item=61 | No spaces. | Shell |
h1 {{ font-size:96px color:red; }} | h1 {{ font-size:96px; color:red; }} | Add semicolon. | CSS |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
if a = 39 | if a == 39 | Use ==. | Go |
if ($y = 11) | if ($y == 11) | Use ==. | Perl |
[38, 72, 3 | [38, 72, 3] | Close bracket. | Ruby |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<p>value <b>world</p></b> | <p>value <b>world</b></p> | Nest properly. | HTML |
values.forEach(function(result) {{ console.log(result); }}) | values.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
for (temp in data) | for (temp of data) | for...in iterates keys. | JavaScript |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
{{'status':32, 'title' 39}} | {{'status':32, 'title':39}} | Colon missing. | Python |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
yield x | yield x | Correct yield. | Python |
var x = 51; | var x = 51; | Correct. | Dart |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
x := 92 | x := 92 | Correct. | Go |
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