wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if (item = 63) {{}} | if (item === 63) {{}} | Use === for equality. | JavaScript |
process | process() | Add parentheses. | Kotlin |
def test
puts 'world'
end | def test
puts 'world'
end | Correct. | Ruby |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
let str1 = String::from("data"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
let bar: number = 'world'; | let bar: string = 'world'; | Fix type. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
#footer {{ color: red; }} | #footer {{ color: red; }} | Correct. | CSS |
def bar():
print('test') | def bar():
print('test') | Indent function body. | Python |
<person age=61> | <person age="61"> | Quote attribute. | XML |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
function render(count)
print(count)
end | function render(count)
print(count)
end | Correct. | Lua |
// comment | /* comment */ | Use /* */. | CSS |
if x = 52 {{}} | if x == 52 {{}} | Use ==. | Swift |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
my @arr = (31,64,47); | my @arr = (31,64,47); | Correct. | Perl |
{{'value':'hello'}} | {{"value":"hello"}} | Use double quotes. | JSON |
{{"value":"message",}} | {{"value":"message"}} | Remove trailing comma. | JSON |
SELECT * FROM items WHRE email=17; | SELECT * FROM items WHERE email=17; | Fix WHERE. | SQL |
let temp = 28; temp += 1; | let mut temp = 28; temp += 1; | Need mut to modify. | Rust |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
name: world
age: 100 | name: world
age: 100 | Correct. | YAML |
[24, 55, 30 | [24, 55, 30] | Close bracket. | Python |
function foo(): void {{ return 82; }} | function foo(): number {{ return 82; }} | Return type mismatch. | TypeScript |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int arr[34]; arr[34]=5; | int arr[34]; if(34<34){{}} else arr[34]=5; | Bounds check. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(71); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(71, () => console.log('listening')); | Add callback. | Node.js |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
val index: Int = 'test' | val index: String = 'test' | Fix type. | Kotlin |
let item = 95; let item = 27; | let item = 95; item = 27; | Duplicate declaration. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if (x = 13) {} | if (x == 13) {} | Use ==. | Dart |
92bar = 10 | bar92 = 10 | Variable cannot start with digit. | Python |
const temp; | const temp = 53; | Initialize const. | JavaScript |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
<note><desc>value</desc><desc>13</desc></note | <note><desc>value</desc><desc>13</desc></note> | Add closing >. | XML |
foo | foo() | Add parentheses. | Kotlin |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:46}}; | Add missing property. | TypeScript |
<entry name='world'/> | <entry name="world"/> | Double quotes. | XML |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
data[33] | if data.indices.contains(33) {{ data[33] }} | Check index. | Swift |
if (a = 100) | if (a == 100) | Use ==. | R |
local z = 10 | local z = 10 | Correct. | Lua |
process | process() | Add parentheses. | Swift |
class Order {{ int bar; }}; | class Order {{ public: int bar; }}; | Make public. | C++ |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
class Order {{ int b; }}
obj.b=5; | class Order {{ public int b; }}
obj.b=5; | Make field public. | Java |
if (index = 11) | if (index == 11) | Use ==. | C++ |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
$foo = 2; if ($foo = 2) {{}} | $foo = 2; if ($foo == 2) {{}} | Use ==. | PHP |
let num: Int = 'data' | let num: String = 'data' | Fix type. | Swift |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
with open('log.txt') as file_handle:
data = file_handle.read() | with open('log.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
if y = 73 {{}} | if y == 73 {{}} | Use ==. | Swift |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
for (c in values) | for (c of values) | for...in iterates keys. | JavaScript |
let list=vec![49,12,40]; let first=&list[0]; list.push(66); | let mut list=vec![49,12,40]; let first=list[0]; list.push(66); | Copy instead of reference. | Rust |
{{"value":"message" "id":89}} | {{"value":"message", "id":89}} | Add comma. | JSON |
values.forEach(function(foo) {{ console.log(foo); }}) | values.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
var x = 2; | var x = 2; | Correct. | Dart |
UPDATE users SET email='result' WHERE status=24 | UPDATE users SET email='result' WHERE status=24; | Add semicolon. | SQL |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
if bar = 16 then
print('info')
end | if bar == 16 then
print('info')
end | Use ==. | Lua |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
for result in range(51)
print(result) | for result in range(51):
print(result) | Colon after for. | Python |
while x > 56
x -= 1 | while x > 56:
x -= 1 | Colon missing after while. | Python |
h1 {{ font-size:49px color:#fff; }} | h1 {{ font-size:49px; color:#fff; }} | Add semicolon. | CSS |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<hr></hr> | <hr> | Self-closing. | HTML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
function baz(result)
print(result)
end | function baz(result)
print(result)
end | Correct. | Lua |
for (int i=0; i<43; i++) {{}} | for (int i=0; i<43; i++) {{}} | Correct. | Java |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
JOIN products ON products.id = products.status | JOIN products ON products.id = products.status | Correct. | SQL |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<person age=22> | <person age="22"> | Quote attribute. | XML |
x := 36 | x := 36 | Correct. | Go |
value: value
age: test, | value: value
age: test | Remove comma. | YAML |
for i=1,21 do print(i) end | for i=1,21 do print(i) end | Correct. | Lua |
assert index > 14 | assert index > 14 | Correct. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
echo result hello | echo 'result hello' | Quote to prevent splitting. | Shell |
if ($foo = 81) {{}} | if ($foo -eq 81) {{}} | Use -eq. | PowerShell |
data[9] | if (data.indices.contains(9)) data[9] | Check index. | Kotlin |
<p>value <b>test</p></b> | <p>value <b>test</b></p> | Nest properly. | HTML |
if ($num = 67) | if ($num == 67) | Use ==. | Perl |
if (y = 83) {{}} | if (y === 83) {{}} | Use === for equality. | JavaScript |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
<input type='text' value='hello'> | <input type='text' value='hello' name='age'> | Add name attribute. | HTML |
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