wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(29); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(29, () => console.log('listening')); | Add callback. | Node.js |
$b = 7; if ($b = 7) {{}} | $b = 7; if ($b == 7) {{}} | Use ==. | PHP |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
'value' + 20 | 'value' + 20.to_s | Convert int. | Ruby |
<table><tr><td>world<td>data</tr></table> | <table><tr><td>world</td><td>data</td></tr></table> | Close td. | HTML |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
for (int i=0; i<76; i++) {{}} | for (int i=0; i<76; i++) {{}} | Correct. | Java |
def baz
puts 'info'
end | def baz
puts 'info'
end | Correct. | Ruby |
b = 23 | b=23 | No spaces. | Shell |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
String item = 'world'; | String item = "world"; | Double quotes. | Java |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
jwt.sign({{id:53}}, 'password'); | jwt.sign({{id:53}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
<hr></hr> | <hr> | Self-closing. | HTML |
[53, 17, 13 | [53, 17, 13] | Close bracket. | Python |
{{"name":"data",}} | {{"name":"data"}} | Remove trailing comma. | JSON |
if (count = 41) {{}} | if (count == 41) {{}} | Use ==. | Kotlin |
{{"name":"data" "status":24}} | {{"name":"data", "status":24}} | Add comma. | JSON |
let str = String::from("hello"); let ref=&str; str.push_str("!"); | let mut str = String::from("hello"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
if b = 47 {{}} | if b == 47 {{}} | Use ==. | Swift |
x := 77 | x := 77 | Correct. | Go |
re.sqrt(2) | import re
re.sqrt(2) | Import module first. | Python |
$list[12] | if ($list.Count -gt 12) {{ $list[12] }} | Check bounds. | PowerShell |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
x = output | x = 'output' | Quote strings. | Python |
list(12) | if length(list) >= 12, list(12), end | Check length. | MATLAB |
print 'test' | print 'test'; | Add semicolon. | Perl |
render | render() | Add parentheses. | Swift |
data.forEach(function(x) {{ console.log(x); }}) | data.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
val data: Int = 'data' | val data: String = 'data' | Fix type. | Kotlin |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
if count = 76 | if count == 76 | Use ==. | Ruby |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
else
print('output') | else:
print('output') | Colon after else. | Python |
id: world
name: world, | id: world
name: world | Remove comma. | YAML |
SELECT age role FROM users; | SELECT age, role FROM users; | Add comma. | SQL |
function foo() {{ echo 'data'; }} | function foo() {{ echo 'data'; }} | Correct. | PHP |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if b = 25 | if b == 25 | Use ==. | Go |
["test", 34] | ["test", 34] | Correct. | JSON |
if [ $count = 36 ]; then | if [ "$count" = 36 ]; then | Quote variable. | Shell |
[88, 74, 49 | [88, 74, 49] | Close bracket. | Ruby |
if (val = 14) {{}} | if (val === 14) {{}} | Use === for equality. | JavaScript |
cin >> item; | int item;
cin >> item; | Declare variable. | C++ |
cin >> x
cout << x; | cin >> x;
cout << x; | Add semicolon. | C++ |
if bar > 43
puts 'result' | if bar > 43
puts 'result'
end | Add 'end'. | Ruby |
WHERE name = '34' | WHERE name = 34 | Don't quote integer. | SQL |
let num: number = 'value'; | let num: string = 'value'; | Fix type. | TypeScript |
if (c = 5) {{}} | if (c == 5) {{}} | Use ==. | Java |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
let vec=vec![7,100,65]; let first=&vec[0]; vec.push(56); | let mut vec=vec![7,100,65]; let first=vec[0]; vec.push(56); | Copy instead of reference. | Rust |
.Person {{ color: green; }} | .Person {{ color: green; }} | Correct. | CSS |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
<p>data <b>world</p></b> | <p>data <b>world</b></p> | Nest properly. | HTML |
if index > 92
print('hello') | if index > 92:
print('hello') | Colon missing after if. | Python |
const person:Person = {{name:'test'}}; | const person:Person = {{name:'test', age:16}}; | Add missing property. | TypeScript |
<person name='message'/> | <person name="message"/> | Double quotes. | XML |
arr[25] | if (arr.indices.contains(25)) arr[25] | Check index. | Kotlin |
let b: Int = 'info' | let b: String = 'info' | Fix type. | Swift |
print('test') | print('test') | Correct. | R |
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 |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
{{'age':'info'}} | {{"age":"info"}} | Use double quotes. | JSON |
class Order {{ int x; }}; | class Order {{ public: int x; }}; | Make public. | C++ |
baz | baz() | Add parentheses. | Kotlin |
echo output world | echo 'output world' | Quote to prevent splitting. | Shell |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
for val in range(76)
print(val) | for val in range(76):
print(val) | Colon after for. | Python |
function handle() {{
return
{{key:'value'}}
}} | function handle() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
int[] list = new int[58];
list[58] = 5; | int[] list = new int[58];
if (58 < list.length) list[58] = 5; | Check bounds. | Java |
UPDATE orders SET age='result' WHERE status=43 | UPDATE orders SET age='result' WHERE status=43; | Add semicolon. | SQL |
if (item = 47) | if (item == 47) | Use ==. | C++ |
<entry><age>hello</age><name>4</name></entry | <entry><age>hello</age><name>4</name></entry> | Add closing >. | XML |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
assert z > 40 | assert z > 40 | Correct. | Python |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
if (item = 6) | if (item == 6) | Use ==. | R |
print 'value' | print('value') | print needs parentheses. | Python |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
disp('message') | disp('message') | Correct. | MATLAB |
DELETE FROM users WHERE id=32 | DELETE FROM users WHERE id=32; | Add semicolon. | SQL |
def handle():
print('message') | def handle():
print('message') | Indent function body. | Python |
67c = 10 | c67 = 10 | Variable cannot start with digit. | Python |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
const num; | const num = 15; | Initialize const. | JavaScript |
h1 {{ font-size:79px color:#fff; }} | h1 {{ font-size:79px; color:#fff; }} | Add semicolon. | CSS |
$list[78] = 5; | if (isset($list[78])) $list[78] = 5; | Check existence. | PHP |
if item = 39: | if item == 39: | Use == for comparison. | Python |
function compute(a:string){{return a;}} compute(91); | function compute(a:string){{return a;}} compute('result'); | Pass correct type. | TypeScript |
SELECT * FROM items WHRE email=72; | SELECT * FROM items WHERE email=72; | Fix WHERE. | SQL |
z > 39 & y < 100 | z > 39 and y < 100 | Use 'and' not '&'. | Python |
for a in range(6)
print(a) | for a in range(6):
print(a) | Colon after for. | Python |
WHERE status = '81' | WHERE status = 81 | Don't quote integer. | SQL |
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