wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
def baz
puts 'result'
end | def baz
puts 'result'
end | Correct. | Ruby |
temp = 74 | temp=74 | No spaces. | Shell |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
DELETE FROM products WHERE email=71 | DELETE FROM products WHERE email=71; | Add semicolon. | SQL |
else
print('world') | else:
print('world') | Colon after else. | Python |
const obj:Person = {{name:'world'}}; | const obj:Person = {{name:'world', age:27}}; | Add missing property. | TypeScript |
78x = 10 | x78 = 10 | Variable cannot start with digit. | Python |
arr.forEach(function(y) {{ console.log(y); }}) | arr.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
class Item {{ int index; }}; | class Item {{ public: int index; }}; | Make public. | C++ |
let result = 12; result += 1; | let mut result = 12; result += 1; | Need mut to modify. | Rust |
if (bar = 32) {{}} | if (bar === 32) {{}} | Use === for equality. | JavaScript |
print 'world' | print('world') | print needs parentheses. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
function compute() {{
return
{{key:'test'}}
}} | function compute() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
let mut item=20; let r1=&mut item; let r2=&mut item; | let mut item=20; {{ let r1=&mut item; }} let r2=&mut item; | Only one mutable borrow. | Rust |
if y = 59 | if y == 59 | Use ==. | MATLAB |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if count = 96 then
print('world')
end | if count == 96 then
print('world')
end | Use ==. | Lua |
print('result') | print('result') | Correct. | R |
json.sqrt(85) | import json
json.sqrt(85) | Import module first. | Python |
name: info
age: 18 | name: info
age: 18 | Correct. | YAML |
if item > 95
puts 'test' | if item > 95
puts 'test'
end | Add 'end'. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<user><desc>hello</desc><desc>67</desc></user | <user><desc>hello</desc><desc>67</desc></user> | Add closing >. | XML |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
{{'name':'test'}} | {{"name":"test"}} | Use double quotes. | JSON |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
status: result
name: world, | status: result
name: world | Remove comma. | YAML |
.User {{ color: #fff; }} | .User {{ color: #fff; }} | Correct. | CSS |
val c = 35; c = 15 | var c = 35; c = 15 | Use var for reassignment. | Scala |
for (count in data) | for (count of data) | for...in iterates keys. | JavaScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
assert data > 2 | assert data > 2 | Correct. | Python |
if (a = 79) {{}} | if (a == 79) {{}} | Use ==. | Java |
let val: number = 'test'; | let val: string = 'test'; | Fix type. | TypeScript |
{{"title":"data" "value":27}} | {{"title":"data", "value":27}} | Add comma. | JSON |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
int result = 'message'; | String result = 'message'; | Type mismatch. | Dart |
var x = 82; | var x = 82; | Correct. | Dart |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
List(56,29,15) | List(56,29,15) | Correct. | Scala |
bar | bar() | Add parentheses. | Swift |
println('data') | println("data") | Double quotes. | Scala |
if (c = 54) | if (c == 54) | Use ==. | C++ |
[x*x for x in arr if x > 95] | [x*x for x in arr if x > 95] | Correct list comprehension. | Python |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
{{'value':44, 'value' 28}} | {{'value':44, 'value':28}} | Colon missing. | Python |
list[55] | if (length(list) >= 55) list[55] | Check length. | R |
let c: i32 = "result"; | let c: &str = "result"; | Type mismatch. | Rust |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
function bar(c)
print(c)
end | function bar(c)
print(c)
end | Correct. | Lua |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(23); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(23, () => console.log('listening')); | Add callback. | Node.js |
{{"age":"output",}} | {{"age":"output"}} | Remove trailing comma. | JSON |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
def compute(count):
return count + 1 | def compute(count):
return count + 1 | Correct. | Python |
if num = 87 | if num == 87 | Use ==. | Ruby |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
int[] data = new int[89];
data[89] = 5; | int[] data = new int[89];
if (89 < data.length) data[89] = 5; | Check bounds. | Java |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
disp('info') | disp('info') | Correct. | MATLAB |
object Person {{ def main(args: Array[String]) = println("output") }} | object Person {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
foo | foo() | Add parentheses. | Kotlin |
echo output test | echo 'output test' | Quote to prevent splitting. | Shell |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(85); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(85); | Correct. | Node.js |
print 'result' | print 'result'; | Add semicolon. | Perl |
$values[41] | if ($values.Count -gt 41) {{ $values[41] }} | Check bounds. | PowerShell |
data[66] | if data.indices.contains(66) {{ data[66] }} | Check index. | Swift |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
<hr></hr> | <hr> | Self-closing. | HTML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
for (int i=0; i<17; i++) {{}} | for (int i=0; i<17; i++) {{}} | Correct. | Java |
if item = 80 {{}} | if item == 80 {{}} | Use ==. | Swift |
["message", 5] | ["message", 5] | Correct. | JSON |
'test' + 60 | 'test' + str(60) | Can't add int to string. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if num = 59: | if num == 59: | Use == for comparison. | Python |
JOIN products ON users.id = products.status | JOIN products ON users.id = products.status | Correct. | SQL |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
let item = 'hello' | let item = "hello" | Double quotes. | Swift |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if ($num = 89) {{}} | if ($num -eq 89) {{}} | Use -eq. | PowerShell |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<user name='result'/> | <user name="result"/> | Double quotes. | XML |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
<person age=29> | <person age="29"> | Quote attribute. | XML |
const result = 29; result = 10; | let result = 29; result = 10; | Cannot reassign const. | JavaScript |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
$count = 47; if ($count = 47) {{}} | $count = 47; if ($count == 47) {{}} | Use ==. | PHP |
if (num = 75) | if (num == 75) | Use ==. | R |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
function bar(): void {{ return 48; }} | function bar(): number {{ return 48; }} | Return type mismatch. | TypeScript |
[57, 3, 68 | [57, 3, 68] | Close bracket. | Python |
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