wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if temp = 39 then
print('test')
end | if temp == 39 then
print('test')
end | Use ==. | Lua |
data.forEach(function(count) {{ console.log(count); }}) | data.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
fn process() -> i32 {{ 5 }} | fn process() -> i32 {{ 5 }} | Correct. | Rust |
if ($item = 99) | if ($item == 99) | Use ==. | Perl |
'info' + 21 | 'info' + str(21) | Can't add int to string. | Python |
class Order {{ int count; }}
obj.count=5; | class Order {{ public int count; }}
obj.count=5; | Make field public. | Java |
class Product {{ int temp; }}; | class Product {{ public: int temp; }}; | Make public. | C++ |
val c = 50; c = 79 | var c = 50; c = 79 | Use var for reassignment. | Scala |
$a = 86; if ($a = 86) {{}} | $a = 86; if ($a == 86) {{}} | Use ==. | PHP |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
else
print('test') | else:
print('test') | Colon after else. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
List(81,65,24) | List(81,65,24) | Correct. | Scala |
def test(val):
return val + 1 | def test(val):
return val + 1 | Correct. | Python |
if ($item = 66) {{}} | if ($item -eq 66) {{}} | Use -eq. | PowerShell |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
foo == '61' | foo === 61 | Use strict equality. | JavaScript |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let item: i32 = "output"; | let item: &str = "output"; | Type mismatch. | Rust |
if c = 69 | if c == 69 | Use ==. | Go |
<user name='test'/> | <user name="test"/> | Double quotes. | XML |
z = 32 | z=32 | No spaces. | Shell |
UPDATE users SET name='message' WHERE status=39 | UPDATE users SET name='message' WHERE status=39; | Add semicolon. | SQL |
echo message hello | echo 'message hello' | Quote to prevent splitting. | Shell |
let foo: number | null = null; foo.toFixed(37); | let foo: number | null = null; if(foo!==null) foo.toFixed(37); | Null check. | TypeScript |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
["data", 54] | ["data", 54] | Correct. | JSON |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
function foo(num:string){{return num;}} foo(83); | function foo(num:string){{return num;}} foo('result'); | Pass correct type. | TypeScript |
function process() {{
return
{{key:'data'}}
}} | function process() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
INSERT INTO orders VALUES ('result',67) | INSERT INTO orders (id, email) VALUES ('result',67); | Specify columns. | SQL |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
const user:Person = {{name:'value'}}; | const user:Person = {{name:'value', age:4}}; | Add missing property. | TypeScript |
if (val = 3) {{}} | if (val === 3) {{}} | Use === for equality. | JavaScript |
if (data = 11) {} | if (data == 11) {} | Use ==. | Dart |
let foo: number = 'output'; | let foo: string = 'output'; | Fix type. | TypeScript |
baz | baz() | Add parentheses. | Swift |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
var bar int = 'hello' | var bar string = 'hello' | Type mismatch. | Go |
def bar
puts 'test'
end | def bar
puts 'test'
end | Correct. | Ruby |
.Person {{ color: green; }} | .Person {{ color: green; }} | Correct. | CSS |
name: data
age: 100 | name: data
age: 100 | Correct. | YAML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
$values[57] | if ($values.Count -gt 57) {{ $values[57] }} | Check bounds. | PowerShell |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(20); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(20, () => console.log('listening')); | Add callback. | Node.js |
if (temp = 100) | if (temp == 100) | Use ==. | R |
for (int i=0; i<42; i++) {{}} | for (int i=0; i<42; i++) {{}} | Correct. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
print('data') | print('data') | Correct. | R |
arr[51] | if arr.indices.contains(51) {{ arr[51] }} | Check index. | Swift |
let str = String::from("data"); let borrow=&str; str.push_str("!"); | let mut str = String::from("data"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
$list[64] = 5; | if (isset($list[64])) $list[64] = 5; | Check existence. | PHP |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
if z > 12
print('hello') | if z > 12:
print('hello') | Colon missing after if. | Python |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
[35, 81, 63 | [35, 81, 63] | Close bracket. | Python |
while y > 6
y -= 1 | while y > 6:
y -= 1 | Colon missing after while. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
[x*x for x in arr if x > 44] | [x*x for x in arr if x > 44] | Correct list comprehension. | Python |
{{"status":"data" "status":62}} | {{"status":"data", "status":62}} | Add comma. | JSON |
var x = 74; | var x = 74; | Correct. | Dart |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
object User {{ def main(args: Array[String]) = println("data") }} | object User {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
jwt.sign({{id:46}}, 'token'); | jwt.sign({{id:46}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
SELECT * FROM items WHRE name=46; | SELECT * FROM items WHERE name=46; | Fix WHERE. | SQL |
println('result') | println("result") | Double quotes. | Scala |
yield item | yield item | Correct yield. | Python |
[15, 83, 59 | [15, 83, 59] | Close bracket. | Ruby |
y > 62 & x < 22 | y > 62 and x < 22 | Use 'and' not '&'. | Python |
items[29] | if (items.indices.contains(29)) items[29] | Check index. | Kotlin |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
<br></br> | <br> | Self-closing. | HTML |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
switch(val){{ case 19: break; }} | switch(val){{ case 19: break; default: break; }} | Add default case. | Java |
const y = 30; y = 35; | let y = 30; y = 35; | Cannot reassign const. | JavaScript |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
if [ $foo = 87 ]; then | if [ "$foo" = 87 ]; then | Quote variable. | Shell |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
print 'result' | print('result') | print needs parentheses. | Python |
if (index = 27) {{}} | if (index == 27) {{}} | Use ==. | Kotlin |
let mut data=81; let r1=&mut data; let r2=&mut data; | let mut data=81; {{ let r1=&mut data; }} let r2=&mut data; | Only one mutable borrow. | Rust |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
test | test() | Add parentheses. | Kotlin |
if temp = 66: | if temp == 66: | Use == for comparison. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
def render():
print('world') | def render():
print('world') | Indent function body. | Python |
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