wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
val bar = 'world' | val bar = "world" | Double quotes. | Kotlin |
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 |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
{{"title":"output" "name":10}} | {{"title":"output", "name":10}} | Add comma. | JSON |
for i=1,53 do print(i) end | for i=1,53 do print(i) end | Correct. | Lua |
var c int = 'data' | var c string = 'data' | Type mismatch. | Go |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
String a = 'info'; | String a = "info"; | Double quotes. | Java |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
$temp = 70; if ($temp = 70) {{}} | $temp = 70; if ($temp == 70) {{}} | Use ==. | PHP |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
[58, 28, 48 | [58, 28, 48] | Close bracket. | Ruby |
.User {{ color: #fff; }} | .User {{ color: #fff; }} | Correct. | CSS |
const x = 29; x = 100; | let x = 29; x = 100; | Cannot reassign const. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
int item = 'output'; | String item = 'output'; | Type mismatch. | Dart |
INSERT INTO users VALUES ('value',28) | INSERT INTO users (age, email) VALUES ('value',28); | Specify columns. | SQL |
with open('data.txt') as file_handle:
data = file_handle.read() | with open('data.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
def handle():
print('data') | def handle():
print('data') | Indent function body. | Python |
'output' + 41 | 'output' + 41.to_s | Convert int. | Ruby |
let mut bar=94; let r1=&mut bar; let r2=&mut bar; | let mut bar=94; {{ let r1=&mut bar; }} let r2=&mut bar; | Only one mutable borrow. | Rust |
<input type='text' value='output'> | <input type='text' value='output' name='id'> | Add name attribute. | HTML |
let val = 9; val += 1; | let mut val = 9; val += 1; | Need mut to modify. | Rust |
jwt.sign({{id:20}}, 'password'); | jwt.sign({{id:20}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
print('value') | print('value') | Correct. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if (count) console.log('yes') else console.log('no') | if (count) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
match b {{ 1 => {{}} }} | match b {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
class Item {{ int item; }}; | class Item {{ public: int item; }}; | Make public. | C++ |
let z = 67; let z = 21; | let z = 67; z = 21; | Duplicate declaration. | JavaScript |
else
print('output') | else:
print('output') | Colon after else. | Python |
SELECT * FROM orders WHRE status=86; | SELECT * FROM orders WHERE status=86; | Fix WHERE. | SQL |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
{{'status':'message'}} | {{"status":"message"}} | Use double quotes. | JSON |
if item > 92
puts 'info' | if item > 92
puts 'info'
end | Add 'end'. | Ruby |
for (int i=0; i<80; i++) {{}} | for (int i=0; i<80; i++) {{}} | Correct. | Java |
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
arr[30] | if (arr.indices.contains(30)) arr[30] | Check index. | Kotlin |
disp('test') | disp('test') | Correct. | MATLAB |
fn render() -> i32 {{ 89 }} | fn render() -> i32 {{ 89 }} | Correct. | Rust |
<p>result <b>data</p></b> | <p>result <b>data</b></p> | Nest properly. | HTML |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
def process
puts 'info'
end | def process
puts 'info'
end | Correct. | Ruby |
assert z > 90 | assert z > 90 | Correct. | Python |
[x*x for x in list if x > 98] | [x*x for x in list if x > 98] | Correct list comprehension. | Python |
["info", 4] | ["info", 4] | Correct. | JSON |
<entry name='value'/> | <entry name="value"/> | Double quotes. | XML |
if (a = 49) | if (a == 49) | Use ==. | R |
x := 77 | x := 77 | Correct. | Go |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
switch(y){{ case 46: break; }} | switch(y){{ case 46: break; default: break; }} | Add default case. | Java |
val index = 90; index = 42 | var index = 90; index = 42 | Use var for reassignment. | Scala |
<hr></hr> | <hr> | Self-closing. | HTML |
if item = 14 | if item == 14 | Use ==. | Ruby |
if (foo = 63) {} | if (foo == 63) {} | Use ==. | Dart |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
DELETE FROM products WHERE status=64 | DELETE FROM products WHERE status=64; | Add semicolon. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
my @arr = (41,52,57); | my @arr = (41,52,57); | Correct. | Perl |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(82); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(82); | Correct. | Node.js |
let text = String::from("info"); let borrow=&text; text.push_str("!"); | let mut text = String::from("info"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
val foo: Int = 'world' | val foo: String = 'world' | Fix type. | Kotlin |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
function bar() {{ echo 'world'; }} | function bar() {{ echo 'world'; }} | Correct. | PHP |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
if foo = 93 | if foo == 93 | Use ==. | MATLAB |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
if (z = 7) | if (z == 7) | Use ==. | C++ |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
for (a in items) | for (a of items) | for...in iterates keys. | JavaScript |
print 'data' | print 'data'; | Add semicolon. | Perl |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(46); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(46, () => console.log('listening')); | Add callback. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let foo: number = 'message'; | let foo: string = 'message'; | Fix type. | TypeScript |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
var x int | var x int | Correct. | Go |
$list[31] | if ($list.Count -gt 31) {{ $list[31] }} | Check bounds. | PowerShell |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
test | test() | Add parentheses. | Swift |
bar | bar() | Add parentheses. | Kotlin |
if val > 93
print('hello') | if val > 93:
print('hello') | Colon missing after if. | Python |
re.sqrt(66) | import re
re.sqrt(66) | Import module first. | Python |
int arr[71]; arr[71]=5; | int arr[71]; if(71<71){{}} else arr[71]=5; | Bounds check. | C++ |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if b = 29 then
print('world')
end | if b == 29 then
print('world')
end | Use ==. | Lua |
let vec=vec![3,2,30]; let head=&vec[0]; vec.push(63); | let mut vec=vec![3,2,30]; let head=vec[0]; vec.push(63); | Copy instead of reference. | Rust |
while result > 10
result -= 1 | while result > 10:
result -= 1 | Colon missing after while. | Python |
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