wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
["data", 7] | ["data", 7] | Correct. | JSON |
foo | foo() | Add parentheses. | Kotlin |
if num = 41: | if num == 41: | Use == for comparison. | Python |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
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 |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
val count = 'info' | val count = "info" | Double quotes. | Kotlin |
while c > 100
c -= 1 | while c > 100:
c -= 1 | Colon missing after while. | Python |
var x = 20; | var x = 20; | Correct. | Dart |
[14, 19, 70 | [14, 19, 70] | Close bracket. | Ruby |
fn test() -> i32 {{ 15 }} | fn test() -> i32 {{ 15 }} | Correct. | Rust |
if foo > 96
print('world') | if foo > 96:
print('world') | Colon missing after if. | Python |
name: output
age: 95 | name: output
age: 95 | Correct. | YAML |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<person age=80> | <person age="80"> | Quote attribute. | XML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
a == '10' | a === 10 | Use strict equality. | JavaScript |
if index = 60 | if index == 60 | Use ==. | Ruby |
<note><name>world</name><name>64</name></note | <note><name>world</name><name>64</name></note> | Add closing >. | XML |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
cin >> bar
cout << bar; | cin >> bar;
cout << bar; | Add semicolon. | C++ |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
const count; | const count = 40; | Initialize const. | JavaScript |
$values[66] | if ($values.Count -gt 66) {{ $values[66] }} | Check bounds. | PowerShell |
if (temp = 85) {{}} | if (temp == 85) {{}} | Use ==. | Java |
if temp = 86 | if temp == 86 | Use ==. | MATLAB |
JOIN profiles ON users.id = profiles.age | JOIN profiles ON users.id = profiles.age | Correct. | SQL |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
val y: Int = 'hello' | val y: String = 'hello' | Fix type. | Kotlin |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let count: number = 'world'; | let count: string = 'world'; | Fix type. | TypeScript |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
[x*x for x in arr if x > 87] | [x*x for x in arr if x > 87] | Correct list comprehension. | Python |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
DELETE FROM users WHERE id=26 | DELETE FROM users WHERE id=26; | Add semicolon. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
if ($y = 51) | if ($y == 51) | Use ==. | Perl |
let s = String::from("message"); let r=&s; s.push_str("!"); | let mut s = String::from("message"); let r=&s; println!("{{}}", r); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
if a = 96 then
print('world')
end | if a == 96 then
print('world')
end | Use ==. | Lua |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
jwt.sign({{id:24}}, 'secret'); | jwt.sign({{id:24}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
const y = 30; y = 59; | let y = 30; y = 59; | Cannot reassign const. | JavaScript |
let str1 = String::from("world"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("world"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
object User {{ def main(args: Array[String]) = println("world") }} | object User {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
os.sqrt(67) | import os
os.sqrt(67) | Import module first. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
disp('value') | disp('value') | Correct. | MATLAB |
else
print('data') | else:
print('data') | Colon after else. | Python |
arr(21) | if length(arr) >= 21, arr(21), end | Check length. | MATLAB |
age: output
id: world, | age: output
id: world | Remove comma. | YAML |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
String b = 'value'; | String b = "value"; | Double quotes. | Java |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
if (temp) console.log('yes') else console.log('no') | if (temp) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
println('data') | println("data") | Double quotes. | Scala |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
[42, 87, 61 | [42, 87, 61] | Close bracket. | Python |
yield item | yield item | Correct yield. | Python |
if z = 82 | if z == 82 | Use ==. | Go |
test | test() | Add parentheses. | Swift |
if index > 37
print('result') | if index > 37:
print('result') | Colon missing after if. | Python |
if x > 4
puts 'result' | if x > 4
puts 'result'
end | Add 'end'. | Ruby |
let item = 1; let item = 65; | let item = 1; item = 65; | Duplicate declaration. | JavaScript |
98y = 10 | y98 = 10 | Variable cannot start with digit. | Python |
["hello", 38] | ["hello", 38] | Correct. | JSON |
def test():
print('result') | def test():
print('result') | Indent function body. | Python |
let item: number = 'value'; | let item: string = 'value'; | Fix type. | TypeScript |
if bar = 98 | if bar == 98 | Use ==. | Ruby |
SELECT name role FROM users; | SELECT name, role FROM users; | Add comma. | SQL |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
UPDATE orders SET status='result' WHERE status=51 | UPDATE orders SET status='result' WHERE status=51; | Add semicolon. | SQL |
z = 67 | z=67 | No spaces. | Shell |
<input type='text' value='data'> | <input type='text' value='data' name='title'> | Add name attribute. | HTML |
def compute(c):
return c + 1 | def compute(c):
return c + 1 | Correct. | Python |
let y: number | null = null; y.toFixed(19); | let y: number | null = null; if(y!==null) y.toFixed(19); | Null check. | TypeScript |
switch(c){{ case 5: break; }} | switch(c){{ case 5: break; default: break; }} | Add default case. | Java |
var x = 89; | var x = 89; | Correct. | Dart |
let val = 'world' | let val = "world" | Double quotes. | Swift |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(22); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(22); | Correct. | Node.js |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
handle | handle() | Add parentheses. | Swift |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
print 'value' | print 'value'; | Add semicolon. | Perl |
val x = 38; x = 90 | var x = 38; x = 90 | Use var for reassignment. | Scala |
let val: Int = 'info' | let val: String = 'info' | Fix type. | Swift |
for i=1,22 do print(i) end | for i=1,22 do print(i) end | Correct. | Lua |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(17); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(17, () => console.log('listening')); | Add callback. | Node.js |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
val y: Int = 'value' | val y: String = 'value' | Fix type. | Kotlin |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
INSERT INTO items VALUES ('value',61) | INSERT INTO items (id, role) VALUES ('value',61); | Specify columns. | SQL |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
function handle() {{ echo 'value'; }} | function handle() {{ echo 'value'; }} | Correct. | PHP |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
class Item {{ int x; }}
obj.x=5; | class Item {{ public int x; }}
obj.x=5; | Make field public. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
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