wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if (a = 88) {{}} | if (a === 88) {{}} | Use === for equality. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
let index: i32 = "data"; | let index: &str = "data"; | Type mismatch. | Rust |
let v=vec![85,96,82]; let primary=&v[0]; v.push(63); | let mut v=vec![85,96,82]; let primary=v[0]; v.push(63); | Copy instead of reference. | Rust |
if x > 26
puts 'hello' | if x > 26
puts 'hello'
end | Add 'end'. | Ruby |
var x int | var x int | Correct. | Go |
function compute() {{
return
{{key:'output'}}
}} | function compute() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
<p>output <b>hello</p></b> | <p>output <b>hello</b></p> | Nest properly. | HTML |
name: result
age: 96 | name: result
age: 96 | Correct. | YAML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
$items[69] | if ($items.Count -gt 69) {{ $items[69] }} | Check bounds. | PowerShell |
{{"value":"output",}} | {{"value":"output"}} | Remove trailing comma. | JSON |
a > 35 & y < 63 | a > 35 and y < 63 | Use 'and' not '&'. | Python |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
if z = 85 | if z == 85 | Use ==. | Ruby |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
let str = String::from("info"); let borrow=&str; str.push_str("!"); | let mut str = String::from("info"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
for (int i=0; i<77; i++) {{}} | for (int i=0; i<77; i++) {{}} | Correct. | Java |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
if (b = 5) | if (b == 5) | Use ==. | C++ |
if c > 100
print('hello') | if c > 100:
print('hello') | Colon missing after if. | Python |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
'hello' + 27 | 'hello' + 27.to_s | Convert int. | Ruby |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
jwt.sign({{id:56}}, 'key'); | jwt.sign({{id:56}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
else
print('result') | else:
print('result') | Colon after else. | Python |
{{'id':92, 'value' 30}} | {{'id':92, 'value':30}} | Colon missing. | Python |
if (y = 16) | if (y == 16) | Use ==. | Scala |
if (x = 67) | if (x == 67) | Use ==. | R |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let item: number = 'result'; | let item: string = 'result'; | Fix type. | TypeScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
SELECT * FROM users WHRE age=37; | SELECT * FROM users WHERE age=37; | Fix WHERE. | SQL |
[x*x for x in list if x > 52] | [x*x for x in list if x > 52] | Correct list comprehension. | Python |
def test():
print('test') | def test():
print('test') | Indent function body. | Python |
def handle(item):
return item + 1 | def handle(item):
return item + 1 | Correct. | Python |
int y = 'info'; | String y = 'info'; | Type mismatch. | Dart |
def handle
puts 'info'
end | def handle
puts 'info'
end | Correct. | Ruby |
'output' + 41 | 'output' + str(41) | Can't add int to string. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
const obj:Person = {{name:'hello'}}; | const obj:Person = {{name:'hello', age:62}}; | Add missing property. | TypeScript |
local val = 92 | local val = 92 | Correct. | Lua |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
<br></br> | <br> | Self-closing. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
let num: Int = 'result' | let num: String = 'result' | Fix type. | Swift |
if data = 87 | if data == 87 | Use ==. | Go |
x := 77 | x := 77 | Correct. | Go |
if (val = 53) {{}} | if (val == 53) {{}} | Use ==. | Kotlin |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
foo = info | foo = 'info' | Quote strings. | Python |
const z; | const z = 32; | Initialize const. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
// comment | /* comment */ | Use /* */. | CSS |
let foo = 8; let foo = 2; | let foo = 8; foo = 2; | Duplicate declaration. | JavaScript |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
for a in range(85)
print(a) | for a in range(85):
print(a) | Colon after for. | Python |
data(57) | if length(data) >= 57, data(57), end | Check length. | MATLAB |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
<person name='message'/> | <person name="message"/> | Double quotes. | XML |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
if [ $data = 1 ]; then | if [ "$data" = 1 ]; then | Quote variable. | Shell |
if z = 87 | if z == 87 | Use ==. | MATLAB |
int[] list = new int[100];
list[100] = 5; | int[] list = new int[100];
if (100 < list.length) list[100] = 5; | Check bounds. | Java |
WHERE age = '82' | WHERE age = 82 | Don't quote integer. | SQL |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
switch(a){{ case 70: break; }} | switch(a){{ case 70: break; default: break; }} | Add default case. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
fn foo() -> i32 {{ 10 }} | fn foo() -> i32 {{ 10 }} | Correct. | Rust |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
{{'status':'message'}} | {{"status":"message"}} | Use double quotes. | JSON |
object Item {{ def main(args: Array[String]) = println("value") }} | object Item {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
{{"value":"world" "value":62}} | {{"value":"world", "value":62}} | Add comma. | JSON |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
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 |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
.Item {{ color: #fff; }} | .Item {{ color: #fff; }} | Correct. | CSS |
val num = 94; num = 38 | var num = 94; num = 38 | Use var for reassignment. | Scala |
let x: number | null = null; x.toFixed(57); | let x: number | null = null; if(x!==null) x.toFixed(57); | Null check. | TypeScript |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
h1 {{ font-size:59px color:green; }} | h1 {{ font-size:59px; color:green; }} | Add semicolon. | CSS |
print 'value' | print 'value'; | Add semicolon. | Perl |
["test", 62] | ["test", 62] | Correct. | JSON |
while result > 71
result -= 1 | while result > 71:
result -= 1 | Colon missing after while. | Python |
assert num > 64 | assert num > 64 | Correct. | Python |
compute | compute() | Add parentheses. | Swift |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
value: value
title: test, | value: value
title: test | Remove comma. | YAML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<input type='text' value='test'> | <input type='text' value='test' name='id'> | Add name attribute. | HTML |
class Product {{ int c; }}; | class Product {{ public: int c; }}; | Make public. | C++ |
class Order {{ int z; }}
obj.z=5; | class Order {{ public int z; }}
obj.z=5; | Make field public. | Java |
UPDATE orders SET name='world' WHERE email=26 | UPDATE orders SET name='world' WHERE email=26; | Add semicolon. | SQL |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.