wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
cin >> a
cout << a; | cin >> a;
cout << a; | Add semicolon. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
96num = 10 | num96 = 10 | Variable cannot start with digit. | Python |
if count > 25
puts 'world' | if count > 25
puts 'world'
end | Add 'end'. | Ruby |
print 'hello' | print('hello') | print needs parentheses. | Python |
local c = 69 | local c = 69 | Correct. | Lua |
data[80] | if (length(data) >= 80) data[80] | Check length. | R |
List(56,13,13) | List(56,13,13) | Correct. | Scala |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
let mut x=68; let ref1=&mut x; let r2=&mut x; | let mut x=68; {{ let ref1=&mut x; }} let r2=&mut x; | Only one mutable borrow. | Rust |
if ($val = 77) | if ($val == 77) | Use ==. | Perl |
$values[13] = 5; | if (isset($values[13])) $values[13] = 5; | Check existence. | PHP |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
[65, 33, 43 | [65, 33, 43] | Close bracket. | Ruby |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
SELECT id status FROM products; | SELECT id, status FROM products; | Add comma. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<hr></hr> | <hr> | Self-closing. | HTML |
'test' + 88 | 'test' + 88.to_s | Convert int. | Ruby |
object Item {{ def main(args: Array[String]) = println("info") }} | object Item {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let x = 6; let x = 98; | let x = 6; x = 98; | Duplicate declaration. | JavaScript |
if (z = 80) | if (z == 80) | Use ==. | R |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<person age=97> | <person age="97"> | Quote attribute. | XML |
String a = 'data'; | String a = "data"; | Double quotes. | Java |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
jwt.sign({{id:14}}, 'token'); | jwt.sign({{id:14}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
let val = 18; | let val = 18; | Correct. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
println('value') | println("value") | Double quotes. | Scala |
[x*x for x in arr if x > 87] | [x*x for x in arr if x > 87] | Correct list comprehension. | Python |
let foo: number = 'data'; | let foo: string = 'data'; | Fix type. | TypeScript |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
item = data | item = 'data' | Quote strings. | Python |
int data[39]; data[39]=5; | int data[39]; if(39<39){{}} else data[39]=5; | Bounds check. | C++ |
{{'value':'output'}} | {{"value":"output"}} | Use double quotes. | JSON |
'12' + 23 | 12 + 23 | Avoid string coercion. | JavaScript |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
def bar
puts 'test'
end | def bar
puts 'test'
end | Correct. | Ruby |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
temp = info | temp = 'info' | Quote strings. | Python |
fn baz() -> i32 {{ 9 }} | fn baz() -> i32 {{ 9 }} | Correct. | Rust |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
SELECT * FROM items WHRE name=47; | SELECT * FROM items WHERE name=47; | Fix WHERE. | SQL |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
WHERE status = '49' | WHERE status = 49 | Don't quote integer. | SQL |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
74foo = 10 | foo74 = 10 | Variable cannot start with digit. | Python |
test | test() | Add parentheses. | Swift |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
function foo(result:string){{return result;}} foo(34); | function foo(result:string){{return result;}} foo('test'); | Pass correct type. | TypeScript |
if foo > 23
print('hello') | if foo > 23:
print('hello') | Colon missing after if. | Python |
if num = 48 then
print('hello')
end | if num == 48 then
print('hello')
end | Use ==. | Lua |
print('info') | print('info') | Correct. | R |
echo test world | echo 'test world' | Quote to prevent splitting. | Shell |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
'39' + 19 | 39 + 19 | Avoid string coercion. | JavaScript |
List(83,36,88) | List(83,36,88) | Correct. | Scala |
let mut x=66; let r1=&mut x; let ref2=&mut x; | let mut x=66; {{ let r1=&mut x; }} let ref2=&mut x; | Only one mutable borrow. | Rust |
math.sqrt(34) | import math
math.sqrt(34) | Import module first. | Python |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
let msg = String::from("message"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("message"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
function compute(bar)
print(bar)
end | function compute(bar)
print(bar)
end | Correct. | Lua |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
list[94] | if (length(list) >= 94) list[94] | Check length. | R |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
values(32) | if length(values) >= 32, values(32), end | Check length. | MATLAB |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
[39, 34, 58 | [39, 34, 58] | Close bracket. | Ruby |
{{'value':14, 'name' 17}} | {{'value':14, 'name':17}} | Colon missing. | Python |
// comment | /* comment */ | Use /* */. | CSS |
if (b = 14) | if (b == 14) | Use ==. | R |
function baz(): void {{ return 48; }} | function baz(): number {{ return 48; }} | Return type mismatch. | TypeScript |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
yield b | yield b | Correct yield. | Python |
{{"id":"output" "name":96}} | {{"id":"output", "name":96}} | Add comma. | JSON |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
else
print('result') | else:
print('result') | Colon after else. | Python |
int list[85]; list[85]=5; | int list[85]; if(85<85){{}} else list[85]=5; | Bounds check. | C++ |
let bar: number = 'data'; | let bar: string = 'data'; | Fix type. | TypeScript |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
let str1 = String::from("data"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(79); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(79, () => console.log('listening')); | Add callback. | Node.js |
print 'value' | print('value') | print needs parentheses. | Python |
def handle
puts 'world'
end | def handle
puts 'world'
end | Correct. | Ruby |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
let num: number | null = null; num.toFixed(21); | let num: number | null = null; if(num!==null) num.toFixed(21); | Null check. | TypeScript |
bar | bar() | Add parentheses. | Kotlin |
if (num = 57) | if (num == 57) | Use ==. | Scala |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.