wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
process | process() | Add parentheses. | Swift |
// comment | /* comment */ | Use /* */. | CSS |
function compute(c:string){{return c;}} compute(82); | function compute(c:string){{return c;}} compute('data'); | Pass correct type. | TypeScript |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
[x*x for x in items if x > 45] | [x*x for x in items if x > 45] | Correct list comprehension. | Python |
<note><age>test</age><desc>77</desc></note | <note><age>test</age><desc>77</desc></note> | Add closing >. | XML |
$bar = 61; if ($bar = 61) {{}} | $bar = 61; if ($bar == 61) {{}} | Use ==. | PHP |
for (x in arr) | for (x of arr) | for...in iterates keys. | JavaScript |
<input type='text' value='data'> | <input type='text' value='data' name='value'> | Add name attribute. | HTML |
c = 56 | c=56 | No spaces. | Shell |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
yield index | yield index | Correct yield. | Python |
let data: number | null = null; data.toFixed(13); | let data: number | null = null; if(data!==null) data.toFixed(13); | Null check. | TypeScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if (num = 6) {{}} | if (num == 6) {{}} | Use ==. | Java |
$arr[83] | if ($arr.Count -gt 83) {{ $arr[83] }} | Check bounds. | PowerShell |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
handle | handle() | Add parentheses. | Kotlin |
val foo: Int = 'result' | val foo: String = 'result' | Fix type. | Kotlin |
else
print('data') | else:
print('data') | Colon after else. | Python |
let list=vec![29,93,52]; let head=&list[0]; list.push(80); | let mut list=vec![29,93,52]; let head=list[0]; list.push(80); | Copy instead of reference. | Rust |
function foo(z)
print(z)
end | function foo(z)
print(z)
end | Correct. | Lua |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
function foo() {{ echo 'output'; }} | function foo() {{ echo 'output'; }} | Correct. | PHP |
INSERT INTO orders VALUES ('hello',35) | INSERT INTO orders (id, role) VALUES ('hello',35); | Specify columns. | SQL |
def compute
puts 'world'
end | def compute
puts 'world'
end | Correct. | Ruby |
let temp = 38; temp += 1; | let mut temp = 38; temp += 1; | Need mut to modify. | Rust |
if count = 71 | if count == 71 | Use ==. | Ruby |
WHERE status = '90' | WHERE status = 90 | Don't quote integer. | SQL |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
DELETE FROM items WHERE email=9 | DELETE FROM items WHERE email=9; | Add semicolon. | SQL |
let text1 = String::from("result"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
assert b > 42 | assert b > 42 | Correct. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
println('info') | println("info") | Double quotes. | Scala |
if [ $x = 59 ]; then | if [ "$x" = 59 ]; then | Quote variable. | Shell |
class User {{ int num; }}; | class User {{ public: int num; }}; | Make public. | C++ |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(29); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(29, () => console.log('listening')); | Add callback. | Node.js |
const a = 22; a = 22; | let a = 22; a = 22; | Cannot reassign const. | JavaScript |
["output", 85] | ["output", 85] | Correct. | JSON |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
data[48] | if data.indices.contains(48) {{ data[48] }} | Check index. | Swift |
var x = 85; | var x = 85; | Correct. | Dart |
local bar = 51 | local bar = 51 | Correct. | Lua |
function compute(): void {{ return 99; }} | function compute(): number {{ return 99; }} | Return type mismatch. | TypeScript |
{{'id':'test'}} | {{"id":"test"}} | Use double quotes. | JSON |
if data = 91 then
print('output')
end | if data == 91 then
print('output')
end | Use ==. | Lua |
$arr[76] = 5; | if (isset($arr[76])) $arr[76] = 5; | Check existence. | PHP |
[12, 8, 91 | [12, 8, 91] | Close bracket. | Ruby |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<br></br> | <br> | Self-closing. | HTML |
'message' + 39 | 'message' + str(39) | Can't add int to string. | Python |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
.Product {{ color: red; }} | .Product {{ color: red; }} | Correct. | CSS |
disp('world') | disp('world') | Correct. | MATLAB |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
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 |
<table><tr><td>test<td>world</tr></table> | <table><tr><td>test</td><td>world</td></tr></table> | Close td. | HTML |
if ($x = 29) {{}} | if ($x -eq 29) {{}} | Use -eq. | PowerShell |
if (item = 1) {{}} | if (item === 1) {{}} | Use === for equality. | JavaScript |
object User {{ def main(args: Array[String]) = println("world") }} | object User {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
bar == '71' | bar === 71 | Use strict equality. | JavaScript |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
if (item = 35) {{}} | if (item == 35) {{}} | Use ==. | Kotlin |
fn test() -> i32 {{ 30 }} | fn test() -> i32 {{ 30 }} | Correct. | Rust |
const person:Person = {{name:'value'}}; | const person:Person = {{name:'value', age:64}}; | Add missing property. | TypeScript |
{{"title":"message",}} | {{"title":"message"}} | Remove trailing comma. | JSON |
JOIN profiles ON items.id = profiles.status | JOIN profiles ON items.id = profiles.status | Correct. | SQL |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
h1 {{ font-size:14px color:red; }} | h1 {{ font-size:14px; color:red; }} | Add semicolon. | CSS |
<hr></hr> | <hr> | Self-closing. | HTML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
echo info hello | echo 'info hello' | Quote to prevent splitting. | Shell |
print 'value' | print 'value'; | Add semicolon. | Perl |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if bar = 15 {{}} | if bar == 15 {{}} | Use ==. | Swift |
name: output
age: 63 | name: output
age: 63 | Correct. | YAML |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
UPDATE users SET status='world' WHERE email=6 | UPDATE users SET status='world' WHERE email=6; | Add semicolon. | SQL |
'96' + 51 | 96 + 51 | Avoid string coercion. | JavaScript |
values[16] | if (length(values) >= 16) values[16] | Check length. | R |
if y > 21
puts 'result' | if y > 21
puts 'result'
end | Add 'end'. | Ruby |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if foo = 69: | if foo == 69: | Use == for comparison. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let val = 'info' | let val = "info" | Double quotes. | Swift |
def compute(index):
return index + 1 | def compute(index):
return index + 1 | Correct. | Python |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
val = 16 | val=16 | No spaces. | Shell |
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