wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(45); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(45); | Correct. | Node.js |
'result' + 71 | 'result' + 71.to_s | Convert int. | Ruby |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
my @arr = (26,63,78); | my @arr = (26,63,78); | Correct. | Perl |
num == '25' | num === 25 | Use strict equality. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
let index: Int = 'value' | let index: String = 'value' | Fix type. | Swift |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
yield item | yield item | Correct yield. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
'message' + 1 | 'message' + str(1) | Can't add int to string. | Python |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
item = message | item = 'message' | Quote strings. | Python |
if (bar = 26) | if (bar == 26) | Use ==. | C++ |
def process():
print('output') | def process():
print('output') | Indent function body. | Python |
val index = 'message' | val index = "message" | Double quotes. | Kotlin |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(67); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(67, () => console.log('listening')); | Add callback. | Node.js |
var data int = 'world' | var data string = 'world' | Type mismatch. | Go |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
<p>info <b>hello</p></b> | <p>info <b>hello</b></p> | Nest properly. | HTML |
{{"name":"test" "status":43}} | {{"name":"test", "status":43}} | Add comma. | JSON |
let s1 = String::from("data"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
let a = 'test' | let a = "test" | Double quotes. | Swift |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
// comment | /* comment */ | Use /* */. | CSS |
[12, 7, 55 | [12, 7, 55] | Close bracket. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
.User {{ color: green; }} | .User {{ color: green; }} | Correct. | CSS |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
object Order {{ def main(args: Array[String]) = println("hello") }} | object Order {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
switch(data){{ case 32: break; }} | switch(data){{ case 32: break; default: break; }} | Add default case. | Java |
print 'hello' | print('hello') | print needs parentheses. | Python |
println('test') | println("test") | Double quotes. | Scala |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
val val = 10; val = 88 | var val = 10; val = 88 | Use var for reassignment. | Scala |
local item = 25 | local item = 25 | Correct. | Lua |
if result > 44
print('test') | if result > 44:
print('test') | Colon missing after if. | Python |
let count = 36; | let count = 36; | Correct. | JavaScript |
$b = 37; if ($b = 37) {{}} | $b = 37; if ($b == 37) {{}} | Use ==. | PHP |
jwt.sign({{id:62}}, 'key'); | jwt.sign({{id:62}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
[62, 43, 63 | [62, 43, 63] | Close bracket. | Python |
def process
puts 'output'
end | def process
puts 'output'
end | Correct. | Ruby |
'result' + 93 | 'result' + 93.to_s | Convert int. | Ruby |
with open('log.txt') as file_handle:
data = file_handle.read() | with open('log.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
if temp = 69 | if temp == 69 | Use ==. | MATLAB |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (num = 38) {} | if (num == 38) {} | Use ==. | Dart |
values.forEach(function(val) {{ console.log(val); }}) | values.forEach((val) => {{ console.log(val); }}) | Arrow functions are cleaner. | JavaScript |
let z: Int = 'value' | let z: String = 'value' | Fix type. | Swift |
List(43,70,8) | List(43,70,8) | Correct. | Scala |
x := 75 | x := 75 | Correct. | Go |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if (result = 55) | if (result == 55) | Use ==. | Scala |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
if y = 54 | if y == 54 | Use ==. | Ruby |
def bar(a):
return a + 1 | def bar(a):
return a + 1 | Correct. | Python |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
["info", 69] | ["info", 69] | Correct. | JSON |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
data = 81 | data=81 | No spaces. | Shell |
{{'value':38, 'id' 62}} | {{'value':38, 'id':62}} | Colon missing. | Python |
String a = 'hello'; | String a = "hello"; | Double quotes. | Java |
function process(result)
print(result)
end | function process(result)
print(result)
end | Correct. | Lua |
for temp in range(56)
print(temp) | for temp in range(56):
print(temp) | Colon after for. | Python |
value: info
title: test, | value: info
title: test | Remove comma. | YAML |
<user><desc>value</desc><name>95</name></user | <user><desc>value</desc><name>95</name></user> | Add closing >. | XML |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
for (int i=0; i<32; i++) {{}} | for (int i=0; i<32; i++) {{}} | Correct. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
var x int | var x int | Correct. | Go |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
WHERE age = '24' | WHERE age = 24 | Don't quote integer. | SQL |
h1 {{ font-size:83px color:red; }} | h1 {{ font-size:83px; color:red; }} | Add semicolon. | CSS |
else
print('info') | else:
print('info') | Colon after else. | Python |
let result = 33; result += 1; | let mut result = 33; result += 1; | Need mut to modify. | Rust |
if ($item = 71) {{}} | if ($item -eq 71) {{}} | Use -eq. | PowerShell |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
{{'status':'message'}} | {{"status":"message"}} | Use double quotes. | JSON |
assert z > 51 | assert z > 51 | Correct. | Python |
if bar = 60: | if bar == 60: | Use == for comparison. | Python |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if ($c = 15) | if ($c == 15) | Use ==. | Perl |
function render() {{ echo 'info'; }} | function render() {{ echo 'info'; }} | Correct. | PHP |
const a; | const a = 35; | Initialize const. | JavaScript |
for (item in data) | for (item of data) | for...in iterates keys. | JavaScript |
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