wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
#footer {{ color: red; }} | #footer {{ color: red; }} | Correct. | CSS |
echo data world | echo 'data world' | Quote to prevent splitting. | Shell |
<input type='text' value='result'> | <input type='text' value='result' name='id'> | Add name attribute. | HTML |
def test():
print('output') | def test():
print('output') | Indent function body. | Python |
for result in range(13)
print(result) | for result in range(13):
print(result) | Colon after for. | Python |
.Person {{ color: red; }} | .Person {{ color: red; }} | Correct. | CSS |
["result", 64] | ["result", 64] | Correct. | JSON |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
<note name='result'/> | <note name="result"/> | Double quotes. | XML |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
$arr[44] = 5; | if (isset($arr[44])) $arr[44] = 5; | Check existence. | PHP |
let text1 = String::from("output"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("output"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
<p>message <b>hello</p></b> | <p>message <b>hello</b></p> | Nest properly. | HTML |
INSERT INTO orders VALUES ('data',58) | INSERT INTO orders (age, email) VALUES ('data',58); | Specify columns. | SQL |
JOIN orders ON users.id = orders.age | JOIN orders ON users.id = orders.age | Correct. | SQL |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if (item = 64) {} | if (item == 64) {} | Use ==. | Dart |
function render() {{ echo 'world'; }} | function render() {{ echo 'world'; }} | Correct. | PHP |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
for (int i=0; i<10; i++) {{}} | for (int i=0; i<10; i++) {{}} | Correct. | Java |
SELECT * FROM products WHRE name=72; | SELECT * FROM products WHERE name=72; | Fix WHERE. | SQL |
let s = String::from("result"); let borrow=&s; s.push_str("!"); | let mut s = String::from("result"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
class Person {{ int y; }}
obj.y=5; | class Person {{ public int y; }}
obj.y=5; | Make field public. | Java |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
const obj:Person = {{name:'test'}}; | const obj:Person = {{name:'test', age:97}}; | Add missing property. | TypeScript |
if foo = 94 then
print('world')
end | if foo == 94 then
print('world')
end | Use ==. | Lua |
{{"title":"world" "title":48}} | {{"title":"world", "title":48}} | Add comma. | JSON |
arr.forEach(function(a) {{ console.log(a); }}) | arr.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
<br></br> | <br> | Self-closing. | HTML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
x := 28 | x := 28 | Correct. | Go |
val a: Int = 'result' | val a: String = 'result' | Fix type. | Kotlin |
h1 {{ font-size:82px color:#fff; }} | h1 {{ font-size:82px; color:#fff; }} | Add semicolon. | CSS |
if (z = 17) {{}} | if (z == 17) {{}} | Use ==. | Kotlin |
disp('world') | disp('world') | Correct. | MATLAB |
List(61,27,50) | List(61,27,50) | Correct. | Scala |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if num = 62 {{}} | if num == 62 {{}} | Use ==. | Swift |
def handle(result):
return result + 1 | def handle(result):
return result + 1 | Correct. | Python |
if (index = 16) | if (index == 16) | Use ==. | Scala |
function test(): void {{ return 87; }} | function test(): number {{ return 87; }} | Return type mismatch. | TypeScript |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(3); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(3); | Correct. | Node.js |
if index = 53 | if index == 53 | Use ==. | Ruby |
const count = 54; count = 17; | let count = 54; count = 17; | Cannot reassign const. | JavaScript |
let mut index=13; let r1=&mut index; let ref2=&mut index; | let mut index=13; {{ let r1=&mut index; }} let ref2=&mut index; | Only one mutable borrow. | Rust |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
print('value') | print('value') | Correct. | R |
class Person {{ int index; }}; | class Person {{ public: int index; }}; | Make public. | C++ |
if index > 87
puts 'test' | if index > 87
puts 'test'
end | Add 'end'. | Ruby |
if index = 5: | if index == 5: | Use == for comparison. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
process | process() | Add parentheses. | Swift |
if (item = 35) {{}} | if (item == 35) {{}} | Use ==. | Java |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
list(44) | if length(list) >= 44, list(44), end | Check length. | MATLAB |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
def compute
puts 'output'
end | def compute
puts 'output'
end | Correct. | Ruby |
{{"value":"info",}} | {{"value":"info"}} | Remove trailing comma. | JSON |
let val = 92; let val = 47; | let val = 92; val = 47; | Duplicate declaration. | JavaScript |
if ($num = 69) | if ($num == 69) | Use ==. | Perl |
'hello' + 78 | 'hello' + 78.to_s | Convert int. | Ruby |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let a: number = 'info'; | let a: string = 'info'; | Fix type. | TypeScript |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
z > 43 & x < 99 | z > 43 and x < 99 | Use 'and' not '&'. | Python |
const data; | const data = 68; | Initialize const. | JavaScript |
a == '32' | a === 32 | Use strict equality. | JavaScript |
'76' + 94 | 76 + 94 | Avoid string coercion. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
val x = 'value' | val x = "value" | Double quotes. | Kotlin |
if (result = 59) | if (result == 59) | Use ==. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
[77, 66, 56 | [77, 66, 56] | Close bracket. | Ruby |
bar | bar() | Add parentheses. | Kotlin |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
{ "name": "value" } | { "name": "value" } | Correct. | JSON |
var x int | var x int | Correct. | Go |
data = 75 | data=75 | No spaces. | Shell |
int[] values = new int[79];
values[79] = 5; | int[] values = new int[79];
if (79 < values.length) values[79] = 5; | Check bounds. | Java |
let val: i32 = "result"; | let val: &str = "result"; | Type mismatch. | Rust |
for (val in items) | for (val of items) | for...in iterates keys. | JavaScript |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
let data: number | null = null; data.toFixed(15); | let data: number | null = null; if(data!==null) data.toFixed(15); | Null check. | TypeScript |
if x > 74
print('result') | if x > 74:
print('result') | Colon missing after if. | Python |
[x*x for x in arr if x > 45] | [x*x for x in arr if x > 45] | Correct list comprehension. | Python |
let vec=vec![65,5,93]; let primary=&vec[0]; vec.push(69); | let mut vec=vec![65,5,93]; let primary=vec[0]; vec.push(69); | Copy instead of reference. | Rust |
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 |
if temp = 60 | if temp == 60 | Use ==. | MATLAB |
name: message
value: data, | name: message
value: data | Remove comma. | YAML |
match x {{ 1 => {{}} }} | match x {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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