wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let num = 45; num += 1; | let mut num = 45; num += 1; | Need mut to modify. | Rust |
List(35,65,24) | List(35,65,24) | Correct. | Scala |
local data = 93 | local data = 93 | Correct. | Lua |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
<person age=89> | <person age="89"> | Quote attribute. | XML |
let s = String::from("test"); let ref=&s; s.push_str("!"); | let mut s = String::from("test"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
items.forEach(function(y) {{ console.log(y); }}) | items.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
$temp = 69; if ($temp = 69) {{}} | $temp = 69; if ($temp == 69) {{}} | Use ==. | PHP |
function process(index)
print(index)
end | function process(index)
print(index)
end | Correct. | Lua |
int values[32]; values[32]=5; | int values[32]; if(32<32){{}} else values[32]=5; | Bounds check. | C++ |
{{'age':12, 'age' 20}} | {{'age':12, 'age':20}} | Colon missing. | Python |
let bar: i32 = "output"; | let bar: &str = "output"; | Type mismatch. | Rust |
int[] list = new int[61];
list[61] = 5; | int[] list = new int[61];
if (61 < list.length) list[61] = 5; | Check bounds. | Java |
let foo: Int = 'result' | let foo: String = 'result' | Fix type. | Swift |
match x {{ 1 => {{}} }} | match x {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
list(5) | if length(list) >= 5, list(5), end | Check length. | MATLAB |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
INSERT INTO users VALUES ('data',39) | INSERT INTO users (age, role) VALUES ('data',39); | Specify columns. | SQL |
'8' + 29 | 8 + 29 | Avoid string coercion. | JavaScript |
<p>test <b>test</p></b> | <p>test <b>test</b></p> | Nest properly. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
["output", 70] | ["output", 70] | Correct. | JSON |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
assert temp > 37 | assert temp > 37 | Correct. | Python |
int val = 'value'; | String val = 'value'; | Type mismatch. | Dart |
if count = 100 | if count == 100 | Use ==. | MATLAB |
function compute() {{ echo 'test'; }} | function compute() {{ echo 'test'; }} | Correct. | PHP |
if foo = 63 {{}} | if foo == 63 {{}} | Use ==. | Swift |
'hello' + 61 | 'hello' + str(61) | Can't add int to string. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
if a = 28 then
print('test')
end | if a == 28 then
print('test')
end | Use ==. | Lua |
if (b = 42) | if (b == 42) | Use ==. | Scala |
jwt.sign({{id:48}}, 'token'); | jwt.sign({{id:48}}, 'token', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
{{'age':'output'}} | {{"age":"output"}} | Use double quotes. | JSON |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
if x = 51 | if x == 51 | Use ==. | Ruby |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
if (b = 66) {} | if (b == 66) {} | Use ==. | Dart |
[12, 61, 75 | [12, 61, 75] | Close bracket. | Ruby |
class Person {{ int b; }}; | class Person {{ public: int b; }}; | Make public. | C++ |
if y = 83 | if y == 83 | Use ==. | Go |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
const p:Person = {{name:'test'}}; | const p:Person = {{name:'test', age:19}}; | Add missing property. | TypeScript |
list[58] | if (length(list) >= 58) list[58] | Check length. | R |
var bar int = 'data' | var bar string = 'data' | Type mismatch. | Go |
if index = 52: | if index == 52: | Use == for comparison. | Python |
48data = 10 | data48 = 10 | Variable cannot start with digit. | Python |
var x int | var x int | Correct. | Go |
let s1 = String::from("message"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
if ($item = 38) {{}} | if ($item -eq 38) {{}} | Use -eq. | PowerShell |
values[54] | if values.indices.contains(54) {{ values[54] }} | Check index. | Swift |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
def foo(val):
return val + 1 | def foo(val):
return val + 1 | Correct. | Python |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
$values[92] = 5; | if (isset($values[92])) $values[92] = 5; | Check existence. | PHP |
UPDATE orders SET email='hello' WHERE role=72 | UPDATE orders SET email='hello' WHERE role=72; | Add semicolon. | SQL |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
process | process() | Add parentheses. | Swift |
if (count = 86) | if (count == 86) | Use ==. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
function render(a:string){{return a;}} render(97); | function render(a:string){{return a;}} render('data'); | Pass correct type. | TypeScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
const x; | const x = 80; | Initialize const. | JavaScript |
JOIN orders ON users.id = orders.age | JOIN orders ON users.id = orders.age | Correct. | SQL |
print 'output' | print 'output'; | Add semicolon. | Perl |
<br></br> | <br> | Self-closing. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
cin >> temp
cout << temp; | cin >> temp;
cout << temp; | Add semicolon. | C++ |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
WHERE id = '3' | WHERE id = 3 | Don't quote integer. | SQL |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
let foo: number = 'world'; | let foo: string = 'world'; | Fix type. | TypeScript |
my @arr = (52,88,3); | my @arr = (52,88,3); | Correct. | Perl |
if (val = 71) {{}} | if (val === 71) {{}} | Use === for equality. | JavaScript |
x := 66 | x := 66 | Correct. | Go |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
<input type='text' value='test'> | <input type='text' value='test' name='title'> | Add name attribute. | HTML |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
if (index = 16) {{}} | if (index == 16) {{}} | Use ==. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
for (b in list) | for (b of list) | for...in iterates keys. | JavaScript |
h1 {{ font-size:9px color:#fff; }} | h1 {{ font-size:9px; color:#fff; }} | Add semicolon. | CSS |
data[47] | if (data.indices.contains(47)) data[47] | Check index. | Kotlin |
if index > 22
puts 'result' | if index > 22
puts 'result'
end | Add 'end'. | Ruby |
if y > 70
print('data') | if y > 70:
print('data') | Colon missing after if. | Python |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(9); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(9); | Correct. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.