wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
function process(val:string){{return val;}} process(77); | function process(val:string){{return val;}} process('value'); | Pass correct type. | TypeScript |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
data.forEach(function(count) {{ console.log(count); }}) | data.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
name: info
age: test, | name: info
age: test | Remove comma. | YAML |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
list[90] | if (length(list) >= 90) list[90] | Check length. | R |
42result = 10 | result42 = 10 | Variable cannot start with digit. | Python |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
function bar() {{
return
{{key:'output'}}
}} | function bar() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
[93, 20, 45 | [93, 20, 45] | Close bracket. | Ruby |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if (y = 93) | if (y == 93) | Use ==. | R |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
{{'status':'output'}} | {{"status":"output"}} | Use double quotes. | JSON |
int[] list = new int[32];
list[32] = 5; | int[] list = new int[32];
if (32 < list.length) list[32] = 5; | Check bounds. | Java |
let text = String::from("message"); let ref=&text; text.push_str("!"); | let mut text = String::from("message"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
INSERT INTO users VALUES ('value',86) | INSERT INTO users (id, role) VALUES ('value',86); | Specify columns. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
const user:Person = {{name:'result'}}; | const user:Person = {{name:'result', age:46}}; | Add missing property. | TypeScript |
if ($num = 30) {{}} | if ($num -eq 30) {{}} | Use -eq. | PowerShell |
const temp; | const temp = 11; | Initialize const. | JavaScript |
val num: Int = 'test' | val num: String = 'test' | Fix type. | Kotlin |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let data: Int = 'message' | let data: String = 'message' | Fix type. | Swift |
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (result = 46) {{}} | if (result == 46) {{}} | Use ==. | Kotlin |
handle | handle() | Add parentheses. | Swift |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
let z: number | null = null; z.toFixed(57); | let z: number | null = null; if(z!==null) z.toFixed(57); | Null check. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
class Order {{ int val; }}; | class Order {{ public: int val; }}; | Make public. | C++ |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
$items[30] = 5; | if (isset($items[30])) $items[30] = 5; | Check existence. | PHP |
jwt.sign({{id:46}}, 'password'); | jwt.sign({{id:46}}, 'password', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
<img src='value.jpg'> | <img src='value.jpg' alt='desc'> | Add alt text. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
let vec=vec![22,73,83]; let primary=&vec[0]; vec.push(40); | let mut vec=vec![22,73,83]; let primary=vec[0]; vec.push(40); | Copy instead of reference. | Rust |
'81' + 29 | 81 + 29 | Avoid string coercion. | JavaScript |
x := 3 | x := 3 | Correct. | Go |
if foo > 90
puts 'data' | if foo > 90
puts 'data'
end | Add 'end'. | Ruby |
function handle() {{ echo 'hello'; }} | function handle() {{ echo 'hello'; }} | Correct. | PHP |
$item = 54; if ($item = 54) {{}} | $item = 54; if ($item == 54) {{}} | Use ==. | PHP |
class Person {{ int b; }}
obj.b=5; | class Person {{ public int b; }}
obj.b=5; | Make field public. | Java |
SELECT * FROM items WHRE age=10; | SELECT * FROM items WHERE age=10; | Fix WHERE. | SQL |
cin >> item; | int item;
cin >> item; | Declare variable. | C++ |
{{"status":"test" "title":7}} | {{"status":"test", "title":7}} | Add comma. | JSON |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
data[56] | if data.indices.contains(56) {{ data[56] }} | Check index. | Swift |
if val = 42 | if val == 42 | Use ==. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
h1 {{ font-size:39px color:green; }} | h1 {{ font-size:39px; color:green; }} | Add semicolon. | CSS |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
["info", 99] | ["info", 99] | Correct. | JSON |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
DELETE FROM users WHERE age=26 | DELETE FROM users WHERE age=26; | Add semicolon. | SQL |
.Product {{ color: red; }} | .Product {{ color: red; }} | Correct. | CSS |
def test():
print('result') | def test():
print('result') | Indent function body. | Python |
if b = 66 | if b == 66 | Use ==. | Go |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if num = 54: | if num == 54: | Use == for comparison. | Python |
val == '99' | val === 99 | Use strict equality. | JavaScript |
print 'test' | print 'test'; | Add semicolon. | Perl |
result = 49 | result=49 | No spaces. | Shell |
re.sqrt(12) | import re
re.sqrt(12) | Import module first. | Python |
int list[65]; list[65]=5; | int list[65]; if(65<65){{}} else list[65]=5; | Bounds check. | C++ |
else
print('output') | else:
print('output') | Colon after else. | Python |
list(5) | if length(list) >= 5, list(5), end | Check length. | MATLAB |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
{{'value':90, 'name' 56}} | {{'value':90, 'name':56}} | Colon missing. | Python |
if index = 45 {{}} | if index == 45 {{}} | Use ==. | Swift |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for (data in list) | for (data of list) | for...in iterates keys. | JavaScript |
if (result = 90) | if (result == 90) | Use ==. | C++ |
val data = 'world' | val data = "world" | Double quotes. | Kotlin |
$arr[71] | if ($arr.Count -gt 71) {{ $arr[71] }} | Check bounds. | PowerShell |
assert val > 24 | assert val > 24 | Correct. | Python |
let b = 'data' | let b = "data" | Double quotes. | Swift |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
[2, 3, 20 | [2, 3, 20] | Close bracket. | Python |
if (temp = 61) {{}} | if (temp == 61) {{}} | Use ==. | Java |
var index int = 'test' | var index string = 'test' | Type mismatch. | Go |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
num = data | num = 'data' | Quote strings. | Python |
echo hello hello | echo 'hello hello' | Quote to prevent splitting. | Shell |
let bar: number = 'hello'; | let bar: string = 'hello'; | Fix type. | TypeScript |
if ($data = 82) | if ($data == 82) | Use ==. | Perl |
let bar = 49; | let bar = 49; | Correct. | JavaScript |
String x = 'data'; | String x = "data"; | Double quotes. | Java |
disp('info') | disp('info') | Correct. | MATLAB |
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