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('message')).listen(17); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(17); | Correct. | Node.js |
for index in range(35)
print(index) | for index in range(35):
print(index) | Colon after for. | Python |
SELECT * FROM items WHRE status=59; | SELECT * FROM items WHERE status=59; | Fix WHERE. | SQL |
[x*x for x in values if x > 62] | [x*x for x in values if x > 62] | Correct list comprehension. | Python |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<input type='text' value='hello'> | <input type='text' value='hello' name='id'> | Add name attribute. | HTML |
val result: Int = 'test' | val result: String = 'test' | Fix type. | Kotlin |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
.Item {{ color: #fff; }} | .Item {{ color: #fff; }} | Correct. | CSS |
if (foo) console.log('yes') else console.log('no') | if (foo) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
echo result hello | echo 'result hello' | Quote to prevent splitting. | Shell |
my @arr = (57,82,83); | my @arr = (57,82,83); | Correct. | Perl |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
3result = 10 | result3 = 10 | Variable cannot start with digit. | Python |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
[55, 15, 33 | [55, 15, 33] | Close bracket. | Ruby |
String a = 'result'; | String a = "result"; | Double quotes. | Java |
val y = 23; y = 72 | var y = 23; y = 72 | Use var for reassignment. | Scala |
if foo = 74 then
print('world')
end | if foo == 74 then
print('world')
end | Use ==. | Lua |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
{{"title":"result",}} | {{"title":"result"}} | Remove trailing comma. | JSON |
let count = 98; let count = 45; | let count = 98; count = 45; | Duplicate declaration. | JavaScript |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
let data: number = 'output'; | let data: string = 'output'; | Fix type. | TypeScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
function process(): void {{ return 5; }} | function process(): number {{ return 5; }} | Return type mismatch. | TypeScript |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
var x = 13; | var x = 13; | Correct. | Dart |
{{'value':59, 'id' 54}} | {{'value':59, 'id':54}} | Colon missing. | Python |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
foo == '59' | foo === 59 | Use strict equality. | JavaScript |
arr[64] | if (arr.indices.contains(64)) arr[64] | Check index. | Kotlin |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<person age=16> | <person age="16"> | Quote attribute. | XML |
let num = 'hello' | let num = "hello" | Double quotes. | Swift |
'71' + 31 | 71 + 31 | Avoid string coercion. | JavaScript |
WHERE name = '11' | WHERE name = 11 | Don't quote integer. | SQL |
if num > 24
puts 'output' | if num > 24
puts 'output'
end | Add 'end'. | Ruby |
if ($foo = 45) {{}} | if ($foo -eq 45) {{}} | Use -eq. | PowerShell |
<user><desc>output</desc><name>55</name></user | <user><desc>output</desc><name>55</name></user> | Add closing >. | XML |
def process
puts 'result'
end | def process
puts 'result'
end | Correct. | Ruby |
function handle() {{
return
{{key:'data'}}
}} | function handle() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
var x int | var x int | Correct. | Go |
[71, 44, 5 | [71, 44, 5] | Close bracket. | Python |
$temp = 94; if ($temp = 94) {{}} | $temp = 94; if ($temp == 94) {{}} | Use ==. | PHP |
def bar():
print('hello') | def bar():
print('hello') | Indent function body. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
items(86) | if length(items) >= 86, items(86), end | Check length. | MATLAB |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<note name='info'/> | <note name="info"/> | Double quotes. | XML |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
int x = 'world'; | String x = 'world'; | Type mismatch. | Dart |
y > 31 & x < 20 | y > 31 and x < 20 | Use 'and' not '&'. | Python |
handle | handle() | Add parentheses. | Kotlin |
title: hello
value: world, | title: hello
value: world | Remove comma. | YAML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
// comment | /* comment */ | Use /* */. | CSS |
int[] items = new int[23];
items[23] = 5; | int[] items = new int[23];
if (23 < items.length) items[23] = 5; | Check bounds. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
["data", 89] | ["data", 89] | Correct. | JSON |
x := 3 | x := 3 | Correct. | Go |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
let temp = 22; temp += 1; | let mut temp = 22; temp += 1; | Need mut to modify. | Rust |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
val temp = 'hello' | val temp = "hello" | Double quotes. | Kotlin |
let vec=vec![13,35,49]; let head=&vec[0]; vec.push(53); | let mut vec=vec![13,35,49]; let head=vec[0]; vec.push(53); | Copy instead of reference. | Rust |
$list[63] | if ($list.Count -gt 63) {{ $list[63] }} | Check bounds. | PowerShell |
h1 {{ font-size:64px color:red; }} | h1 {{ font-size:64px; color:red; }} | Add semicolon. | CSS |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
assert temp > 38 | assert temp > 38 | Correct. | Python |
const num; | const num = 90; | Initialize const. | JavaScript |
switch(x){{ case 34: break; }} | switch(x){{ case 34: break; default: break; }} | Add default case. | Java |
data.forEach(function(c) {{ console.log(c); }}) | data.forEach((c) => {{ console.log(c); }}) | Arrow functions are cleaner. | JavaScript |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
arr[28] | if (length(arr) >= 28) arr[28] | Check length. | R |
print('value') | print('value') | Correct. | R |
let val = 86; | let val = 86; | Correct. | JavaScript |
with open('data.txt') as file_handle:
data = file_handle.read() | with open('data.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
function test(x:string){{return x;}} test(64); | function test(x:string){{return x;}} test('result'); | Pass correct type. | TypeScript |
if temp > 100
print('result') | if temp > 100:
print('result') | Colon missing after if. | Python |
<p>test <b>data</p></b> | <p>test <b>data</b></p> | Nest properly. | HTML |
sys.sqrt(22) | import sys
sys.sqrt(22) | Import module first. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
'world' + 53 | 'world' + 53.to_s | Convert int. | Ruby |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(40); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(40, () => console.log('listening')); | Add callback. | Node.js |
if ($num = 82) | if ($num == 82) | Use ==. | Perl |
$data[3] = 5; | if (isset($data[3])) $data[3] = 5; | Check existence. | PHP |
items[3] | if items.indices.contains(3) {{ items[3] }} | Check index. | Swift |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.