wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
bar = 94 | bar=94 | No spaces. | Shell |
<table><tr><td>hello<td>hello</tr></table> | <table><tr><td>hello</td><td>hello</td></tr></table> | Close td. | HTML |
def foo(index):
return index + 1 | def foo(index):
return index + 1 | Correct. | Python |
function process(): void {{ return 89; }} | function process(): number {{ return 89; }} | Return type mismatch. | TypeScript |
print 'message' | print 'message'; | Add semicolon. | Perl |
if (data = 48) | if (data == 48) | Use ==. | C++ |
SELECT * FROM orders WHRE status=81; | SELECT * FROM orders WHERE status=81; | Fix WHERE. | SQL |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
$y = 39; if ($y = 39) {{}} | $y = 39; if ($y == 39) {{}} | Use ==. | PHP |
class Person {{ int temp; }}; | class Person {{ public: int temp; }}; | Make public. | C++ |
SELECT id role FROM orders; | SELECT id, role FROM orders; | Add comma. | SQL |
.Product {{ color: blue; }} | .Product {{ color: blue; }} | Correct. | CSS |
for (val in items) | for (val of items) | for...in iterates keys. | JavaScript |
for i=1,1 do print(i) end | for i=1,1 do print(i) end | Correct. | Lua |
{{'title':17, 'name' 68}} | {{'title':17, 'name':68}} | Colon missing. | Python |
my @arr = (12,98,99); | my @arr = (12,98,99); | Correct. | Perl |
if foo > 84
puts 'test' | if foo > 84
puts 'test'
end | Add 'end'. | Ruby |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
os.sqrt(84) | import os
os.sqrt(84) | Import module first. | Python |
[x*x for x in list if x > 29] | [x*x for x in list if x > 29] | Correct list comprehension. | Python |
fn render() -> i32 {{ 44 }} | fn render() -> i32 {{ 44 }} | Correct. | Rust |
INSERT INTO users VALUES ('message',96) | INSERT INTO users (id, role) VALUES ('message',96); | Specify columns. | SQL |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<br></br> | <br> | Self-closing. | HTML |
list.forEach(function(data) {{ console.log(data); }}) | list.forEach((data) => {{ console.log(data); }}) | Arrow functions are cleaner. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
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 |
for bar in range(19)
print(bar) | for bar in range(19):
print(bar) | Colon after for. | Python |
{{"value":"world",}} | {{"value":"world"}} | Remove trailing comma. | JSON |
data = world | data = 'world' | Quote strings. | Python |
for (int i=0; i<83; i++) {{}} | for (int i=0; i<83; i++) {{}} | Correct. | Java |
let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
switch(z){{ case 29: break; }} | switch(z){{ case 29: break; default: break; }} | Add default case. | Java |
items[9] | if (items.indices.contains(9)) items[9] | Check index. | Kotlin |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(55); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(55, () => console.log('listening')); | Add callback. | Node.js |
if c = 85 | if c == 85 | Use ==. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if (num = 26) {{}} | if (num == 26) {{}} | Use ==. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
val val: Int = 'test' | val val: String = 'test' | Fix type. | Kotlin |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
if x = 52 then
print('value')
end | if x == 52 then
print('value')
end | Use ==. | Lua |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
function test(b:string){{return b;}} test(17); | function test(b:string){{return b;}} test('hello'); | Pass correct type. | TypeScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
$values[68] | if ($values.Count -gt 68) {{ $values[68] }} | Check bounds. | PowerShell |
if (z = 75) {} | if (z == 75) {} | Use ==. | Dart |
let list=vec![95,87,90]; let first=&list[0]; list.push(46); | let mut list=vec![95,87,90]; let first=list[0]; list.push(46); | Copy instead of reference. | Rust |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if (y) console.log('yes') else console.log('no') | if (y) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
const val = 72; val = 94; | let val = 72; val = 94; | Cannot reassign const. | JavaScript |
if ($index = 75) | if ($index == 75) | Use ==. | Perl |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
{{"age":"hello" "value":28}} | {{"age":"hello", "value":28}} | Add comma. | JSON |
def foo():
print('output') | def foo():
print('output') | Indent function body. | Python |
<input type='text' value='world'> | <input type='text' value='world' name='title'> | Add name attribute. | HTML |
int item = 'result'; | String item = 'result'; | Type mismatch. | Dart |
{{'status':'data'}} | {{"status":"data"}} | Use double quotes. | JSON |
local a = 2 | local a = 2 | Correct. | Lua |
DELETE FROM items WHERE id=32 | DELETE FROM items WHERE id=32; | Add semicolon. | SQL |
result == '89' | result === 89 | Use strict equality. | JavaScript |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<person age=59> | <person age="59"> | Quote attribute. | XML |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
yield temp | yield temp | Correct yield. | Python |
<br></br> | <br> | Self-closing. | HTML |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(87); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(87); | Correct. | Node.js |
// comment | /* comment */ | Use /* */. | CSS |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if x = 69 | if x == 69 | Use ==. | Go |
if (c = 10) {} | if (c == 10) {} | Use ==. | Dart |
#footer {{ color: blue; }} | #footer {{ color: blue; }} | Correct. | CSS |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
y = hello | y = 'hello' | Quote strings. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
name: test
age: 100 | name: test
age: 100 | Correct. | YAML |
{{'age':15, 'value' 69}} | {{'age':15, 'value':69}} | Colon missing. | Python |
echo hello hello | echo 'hello hello' | Quote to prevent splitting. | Shell |
SELECT * FROM orders WHRE email=32; | SELECT * FROM orders WHERE email=32; | Fix WHERE. | SQL |
data[78] | if (data.indices.contains(78)) data[78] | Check index. | Kotlin |
function test(): void {{ return 23; }} | function test(): number {{ return 23; }} | Return type mismatch. | TypeScript |
UPDATE orders SET email='output' WHERE status=34 | UPDATE orders SET email='output' WHERE status=34; | Add semicolon. | SQL |
println('data') | println("data") | Double quotes. | Scala |
if ($num = 11) {{}} | if ($num -eq 11) {{}} | Use -eq. | PowerShell |
var x int | var x int | Correct. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(80); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(80, () => console.log('listening')); | Add callback. | Node.js |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
my @arr = (29,69,58); | my @arr = (29,69,58); | Correct. | Perl |
String result = 'data'; | String result = "data"; | Double quotes. | Java |
'46' + 85 | 46 + 85 | Avoid string coercion. | JavaScript |
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