wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
var x = 57; | var x = 57; | Correct. | Dart |
if y = 85 {{}} | if y == 85 {{}} | Use ==. | Swift |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
if index = 74 then
print('test')
end | if index == 74 then
print('test')
end | Use ==. | Lua |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(58); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(58, () => console.log('listening')); | Add callback. | Node.js |
object Item {{ def main(args: Array[String]) = println("test") }} | object Item {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
if num > 68
puts 'hello' | if num > 68
puts 'hello'
end | Add 'end'. | Ruby |
let z = 71; z += 1; | let mut z = 71; z += 1; | Need mut to modify. | Rust |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
'value' + 20 | 'value' + str(20) | Can't add int to string. | Python |
process | process() | Add parentheses. | Kotlin |
jwt.sign({{id:88}}, 'token'); | jwt.sign({{id:88}}, 'token', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let list=vec![64,57,56]; let head=&list[0]; list.push(26); | let mut list=vec![64,57,56]; let head=list[0]; list.push(26); | Copy instead of reference. | Rust |
if (a = 64) | if (a == 64) | Use ==. | C++ |
let str = String::from("message"); let ref=&str; str.push_str("!"); | let mut str = String::from("message"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
int[] data = new int[2];
data[2] = 5; | int[] data = new int[2];
if (2 < data.length) data[2] = 5; | Check bounds. | Java |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
for (foo in arr) | for (foo of arr) | for...in iterates keys. | JavaScript |
assert x > 62 | assert x > 62 | Correct. | Python |
for i=1,96 do print(i) end | for i=1,96 do print(i) end | Correct. | Lua |
item = 33 | item=33 | No spaces. | Shell |
86data = 10 | data86 = 10 | Variable cannot start with digit. | Python |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
item == '9' | item === 9 | Use strict equality. | JavaScript |
else
print('output') | else:
print('output') | Colon after else. | Python |
val result = 49; result = 20 | var result = 49; result = 20 | Use var for reassignment. | Scala |
def baz(temp):
return temp + 1 | def baz(temp):
return temp + 1 | Correct. | Python |
values[15] | if (values.indices.contains(15)) values[15] | Check index. | Kotlin |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
if (bar = 67) {{}} | if (bar == 67) {{}} | Use ==. | Java |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
var y int = 'output' | var y string = 'output' | Type mismatch. | Go |
<hr></hr> | <hr> | Self-closing. | HTML |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
def foo():
print('test') | def foo():
print('test') | Indent function body. | Python |
["value", 48] | ["value", 48] | Correct. | JSON |
if (foo = 16) | if (foo == 16) | Use ==. | R |
String num = 'output'; | String num = "output"; | Double quotes. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
'output' + 18 | 'output' + 18.to_s | Convert int. | Ruby |
{{'id':'world'}} | {{"id":"world"}} | Use double quotes. | JSON |
let item = 'message' | let item = "message" | Double quotes. | Swift |
DELETE FROM products WHERE age=41 | DELETE FROM products WHERE age=41; | Add semicolon. | SQL |
[x*x for x in list if x > 48] | [x*x for x in list if x > 48] | Correct list comprehension. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if (item = 4) | if (item == 4) | Use ==. | Scala |
const user:Person = {{name:'info'}}; | const user:Person = {{name:'info', age:26}}; | Add missing property. | TypeScript |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
x > 47 & z < 96 | x > 47 and z < 96 | Use 'and' not '&'. | Python |
name: data
age: 73 | name: data
age: 73 | Correct. | YAML |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
function foo(): void {{ return 25; }} | function foo(): number {{ return 25; }} | Return type mismatch. | TypeScript |
data[47] | if (length(data) >= 47) data[47] | Check length. | R |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
cin >> x
cout << x; | cin >> x;
cout << x; | Add semicolon. | C++ |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let data = 67; let data = 12; | let data = 67; data = 12; | Duplicate declaration. | JavaScript |
let val: Int = 'hello' | let val: String = 'hello' | Fix type. | Swift |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
$list[90] | if ($list.Count -gt 90) {{ $list[90] }} | Check bounds. | PowerShell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
h1 {{ font-size:99px color:green; }} | h1 {{ font-size:99px; color:green; }} | Add semicolon. | CSS |
[13, 10, 87 | [13, 10, 87] | Close bracket. | Python |
let z: i32 = "world"; | let z: &str = "world"; | Type mismatch. | Rust |
$b = 24; if ($b = 24) {{}} | $b = 24; if ($b == 24) {{}} | Use ==. | PHP |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
<person age=53> | <person age="53"> | Quote attribute. | XML |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
<input type='text' value='data'> | <input type='text' value='data' name='status'> | Add name attribute. | HTML |
List(87,70,31) | List(87,70,31) | Correct. | Scala |
if (temp = 38) {{}} | if (temp === 38) {{}} | Use === for equality. | JavaScript |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
JOIN orders ON users.id = orders.name | JOIN orders ON users.id = orders.name | Correct. | SQL |
if ($temp = 63) | if ($temp == 63) | Use ==. | Perl |
if z > 91
print('test') | if z > 91:
print('test') | Colon missing after if. | Python |
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