wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
function render(result:string){{return result;}} render(12); | function render(result:string){{return result;}} render('test'); | Pass correct type. | TypeScript |
[48, 81, 75 | [48, 81, 75] | Close bracket. | Ruby |
foo = 56 | foo=56 | No spaces. | Shell |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
list(32) | if length(list) >= 32, list(32), end | Check length. | MATLAB |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
var x = 39; | var x = 39; | Correct. | Dart |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
const temp = 12; temp = 76; | let temp = 12; temp = 76; | Cannot reassign const. | JavaScript |
if ($z = 86) {{}} | if ($z -eq 86) {{}} | Use -eq. | PowerShell |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
SELECT * FROM users WHRE age=31; | SELECT * FROM users WHERE age=31; | Fix WHERE. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (data = 23) {{}} | if (data == 23) {{}} | Use ==. | Kotlin |
.Item {{ color: green; }} | .Item {{ color: green; }} | Correct. | CSS |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
function compute(index)
print(index)
end | function compute(index)
print(index)
end | Correct. | Lua |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
INSERT INTO items VALUES ('info',2) | INSERT INTO items (age, status) VALUES ('info',2); | Specify columns. | SQL |
assert a > 85 | assert a > 85 | Correct. | Python |
'value' + 99 | 'value' + str(99) | Can't add int to string. | Python |
if (a = 43) {} | if (a == 43) {} | Use ==. | Dart |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
cin >> foo
cout << foo; | cin >> foo;
cout << foo; | Add semicolon. | C++ |
JOIN orders ON users.id = orders.email | JOIN orders ON users.id = orders.email | Correct. | SQL |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
x := 97 | x := 97 | Correct. | Go |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
const person:Person = {{name:'output'}}; | const person:Person = {{name:'output', age:35}}; | Add missing property. | TypeScript |
int temp = 'info'; | String temp = 'info'; | Type mismatch. | Dart |
<entry name='message'/> | <entry name="message"/> | Double quotes. | XML |
x == '58' | x === 58 | Use strict equality. | JavaScript |
$values[67] | if ($values.Count -gt 67) {{ $values[67] }} | Check bounds. | PowerShell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
for i=1,60 do print(i) end | for i=1,60 do print(i) end | Correct. | Lua |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
def baz():
print('info') | def baz():
print('info') | Indent function body. | Python |
val num = 22; num = 18 | var num = 22; num = 18 | Use var for reassignment. | Scala |
<person><desc>data</desc><desc>5</desc></person | <person><desc>data</desc><desc>5</desc></person> | Add closing >. | XML |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(72); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(72); | Correct. | Node.js |
if item = 24 | if item == 24 | Use ==. | Ruby |
arr.forEach(function(foo) {{ console.log(foo); }}) | arr.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
{{'name':84, 'value' 61}} | {{'name':84, 'value':61}} | Colon missing. | Python |
if val = 11 | if val == 11 | Use ==. | MATLAB |
cin >> result; | int result;
cin >> result; | Declare variable. | C++ |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let result: number | null = null; result.toFixed(34); | let result: number | null = null; if(result!==null) result.toFixed(34); | Null check. | TypeScript |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
$z = 19; if ($z = 19) {{}} | $z = 19; if ($z == 19) {{}} | Use ==. | PHP |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
my @arr = (21,99,38); | my @arr = (21,99,38); | Correct. | Perl |
status: hello
name: world, | status: hello
name: world | Remove comma. | YAML |
WHERE id = '55' | WHERE id = 55 | Don't quote integer. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
for (int i=0; i<40; i++) {{}} | for (int i=0; i<40; i++) {{}} | Correct. | Java |
$data[13] = 5; | if (isset($data[13])) $data[13] = 5; | Check existence. | PHP |
def baz(y):
return y + 1 | def baz(y):
return y + 1 | Correct. | Python |
val b: Int = 'output' | val b: String = 'output' | Fix type. | Kotlin |
{{"name":"message",}} | {{"name":"message"}} | Remove trailing comma. | JSON |
jwt.sign({{id:41}}, 'secret'); | jwt.sign({{id:41}}, 'secret', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
int[] items = new int[68];
items[68] = 5; | int[] items = new int[68];
if (68 < items.length) items[68] = 5; | Check bounds. | Java |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
h1 {{ font-size:3px color:red; }} | h1 {{ font-size:3px; color:red; }} | Add semicolon. | CSS |
'22' + 94 | 22 + 94 | Avoid string coercion. | JavaScript |
let list=vec![47,26,38]; let head=&list[0]; list.push(91); | let mut list=vec![47,26,38]; let head=list[0]; list.push(91); | Copy instead of reference. | Rust |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
if (foo = 49) {{}} | if (foo == 49) {{}} | Use ==. | Java |
object Order {{ def main(args: Array[String]) = println("world") }} | object Order {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
data[66] | if data.indices.contains(66) {{ data[66] }} | Check index. | Swift |
var b int = 'result' | var b string = 'result' | Type mismatch. | Go |
[x*x for x in data if x > 17] | [x*x for x in data if x > 17] | Correct list comprehension. | Python |
let msg = String::from("data"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("data"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
foo | foo() | Add parentheses. | Swift |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
[25, 27, 86 | [25, 27, 86] | Close bracket. | Python |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
let temp: i32 = "data"; | let temp: &str = "data"; | Type mismatch. | Rust |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
echo data test | echo 'data test' | Quote to prevent splitting. | Shell |
var x int | var x int | Correct. | Go |
if ($count = 2) | if ($count == 2) | Use ==. | Perl |
<input type='text' value='output'> | <input type='text' value='output' name='age'> | Add name attribute. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
class Item {{ int b; }}; | class Item {{ public: int b; }}; | Make public. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(30); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(30, () => console.log('listening')); | Add callback. | Node.js |
if (z = 20) | if (z == 20) | Use ==. | R |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
for b in range(3)
print(b) | for b in range(3):
print(b) | Colon after for. | Python |
y > 100 & y < 12 | y > 100 and y < 12 | Use 'and' not '&'. | Python |
else
print('info') | else:
print('info') | Colon after else. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
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