wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
val = hello | val = 'hello' | Quote strings. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
<p>message <b>world</p></b> | <p>message <b>world</b></p> | Nest properly. | HTML |
if ($foo = 12) {{}} | if ($foo -eq 12) {{}} | Use -eq. | PowerShell |
if ($foo = 35) | if ($foo == 35) | Use ==. | Perl |
if val = 70 then
print('result')
end | if val == 70 then
print('result')
end | Use ==. | Lua |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
var temp int = 'message' | var temp string = 'message' | Type mismatch. | Go |
sys.sqrt(98) | import sys
sys.sqrt(98) | Import module first. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let v=vec![33,5,15]; let first=&v[0]; v.push(77); | let mut v=vec![33,5,15]; let first=v[0]; v.push(77); | Copy instead of reference. | Rust |
'hello' + 63 | 'hello' + 63.to_s | Convert int. | Ruby |
if z > 42
print('test') | if z > 42:
print('test') | Colon missing after if. | Python |
a > 79 & b < 51 | a > 79 and b < 51 | Use 'and' not '&'. | Python |
list[24] | if (length(list) >= 24) list[24] | Check length. | R |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
<note><desc>world</desc><desc>61</desc></note | <note><desc>world</desc><desc>61</desc></note> | Add closing >. | XML |
<br></br> | <br> | Self-closing. | HTML |
const num = 68; num = 30; | let num = 68; num = 30; | Cannot reassign const. | JavaScript |
if data = 84 {{}} | if data == 84 {{}} | Use ==. | Swift |
function test(): void {{ return 73; }} | function test(): number {{ return 73; }} | Return type mismatch. | TypeScript |
int x = 'info'; | String x = 'info'; | Type mismatch. | Dart |
{{'status':60, 'id' 22}} | {{'status':60, 'id':22}} | Colon missing. | Python |
bar = 42 | bar=42 | No spaces. | Shell |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
function process(z)
print(z)
end | function process(z)
print(z)
end | Correct. | Lua |
for (int i=0; i<38; i++) {{}} | for (int i=0; i<38; i++) {{}} | Correct. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if (bar = 9) {{}} | if (bar == 9) {{}} | Use ==. | Java |
let str = String::from("output"); let borrow=&str; str.push_str("!"); | let mut str = String::from("output"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
my @arr = (37,12,33); | my @arr = (37,12,33); | Correct. | Perl |
70item = 10 | item70 = 10 | Variable cannot start with digit. | Python |
if val = 51: | if val == 51: | Use == for comparison. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
for val in range(38)
print(val) | for val in range(38):
print(val) | Colon after for. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
local item = 100 | local item = 100 | Correct. | Lua |
for (count in items) | for (count of items) | for...in iterates keys. | JavaScript |
class Order {{ int count; }}
obj.count=5; | class Order {{ public int count; }}
obj.count=5; | Make field public. | Java |
fn foo() -> i32 {{ 35 }} | fn foo() -> i32 {{ 35 }} | Correct. | Rust |
SELECT age status FROM users; | SELECT age, status FROM users; | Add comma. | SQL |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
{{'name':'message'}} | {{"name":"message"}} | Use double quotes. | JSON |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
let item = 'test' | let item = "test" | Double quotes. | Swift |
$list[77] = 5; | if (isset($list[77])) $list[77] = 5; | Check existence. | PHP |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
process | process() | Add parentheses. | Kotlin |
name: data
title: test, | name: data
title: test | Remove comma. | YAML |
// comment | /* comment */ | Use /* */. | CSS |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
if item = 12 | if item == 12 | Use ==. | Go |
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 |
UPDATE items SET name='data' WHERE role=38 | UPDATE items SET name='data' WHERE role=38; | Add semicolon. | SQL |
for i=1,57 do print(i) end | for i=1,57 do print(i) end | Correct. | Lua |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
assert b > 7 | assert b > 7 | Correct. | Python |
object Product {{ def main(args: Array[String]) = println("test") }} | object Product {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
<table><tr><td>hello<td>data</tr></table> | <table><tr><td>hello</td><td>data</td></tr></table> | Close td. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
let y: number = 'info'; | let y: string = 'info'; | Fix type. | TypeScript |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
<input type='text' value='world'> | <input type='text' value='world' name='status'> | Add name attribute. | HTML |
if (val = 88) | if (val == 88) | Use ==. | Scala |
values.forEach(function(result) {{ console.log(result); }}) | values.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
let data: number | null = null; data.toFixed(83); | let data: number | null = null; if(data!==null) data.toFixed(83); | Null check. | TypeScript |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
print('world') | print('world') | Correct. | R |
println('result') | println("result") | Double quotes. | Scala |
if a = 66 | if a == 66 | Use ==. | Ruby |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
let num = 31; let num = 61; | let num = 31; num = 61; | Duplicate declaration. | JavaScript |
def foo(data):
return data + 1 | def foo(data):
return data + 1 | Correct. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
[100, 24, 89 | [100, 24, 89] | Close bracket. | Python |
let a: Int = 'world' | let a: String = 'world' | Fix type. | Swift |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
INSERT INTO items VALUES ('value',80) | INSERT INTO items (id, role) VALUES ('value',80); | Specify columns. | SQL |
val data = 96; data = 20 | var data = 96; data = 20 | Use var for reassignment. | Scala |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
if (data = 70) {{}} | if (data == 70) {{}} | Use ==. | Kotlin |
disp('result') | disp('result') | Correct. | MATLAB |
[38, 42, 60 | [38, 42, 60] | Close bracket. | Ruby |
int values[68]; values[68]=5; | int values[68]; if(68<68){{}} else values[68]=5; | Bounds check. | C++ |
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