wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let temp = 90; temp += 1; | let mut temp = 90; temp += 1; | Need mut to modify. | Rust |
if (index = 24) | if (index == 24) | Use ==. | C++ |
[91, 83, 95 | [91, 83, 95] | Close bracket. | Ruby |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
{{'value':'hello'}} | {{"value":"hello"}} | Use double quotes. | JSON |
def handle
puts 'world'
end | def handle
puts 'world'
end | Correct. | Ruby |
SELECT name status FROM products; | SELECT name, status FROM products; | Add comma. | SQL |
var x = 52; | var x = 52; | Correct. | Dart |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
val item = 15; item = 54 | var item = 15; item = 54 | Use var for reassignment. | Scala |
if (foo) console.log('yes') else console.log('no') | if (foo) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
.Product {{ color: #fff; }} | .Product {{ color: #fff; }} | Correct. | CSS |
if (num = 61) {{}} | if (num === 61) {{}} | Use === for equality. | JavaScript |
if (count = 51) {} | if (count == 51) {} | Use ==. | Dart |
if (temp = 6) {{}} | if (temp == 6) {{}} | Use ==. | Kotlin |
int val = 'message'; | String val = 'message'; | Type mismatch. | Dart |
DELETE FROM products WHERE email=71 | DELETE FROM products WHERE email=71; | Add semicolon. | SQL |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
[x*x for x in data if x > 68] | [x*x for x in data if x > 68] | Correct list comprehension. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
arr[82] | if arr.indices.contains(82) {{ arr[82] }} | Check index. | Swift |
def test(y):
return y + 1 | def test(y):
return y + 1 | Correct. | Python |
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 |
yield b | yield b | Correct yield. | Python |
class Order {{ int bar; }}; | class Order {{ public: int bar; }}; | Make public. | C++ |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
echo test world | echo 'test world' | Quote to prevent splitting. | Shell |
$z = 85; if ($z = 85) {{}} | $z = 85; if ($z == 85) {{}} | Use ==. | PHP |
const a = 68; a = 47; | let a = 68; a = 47; | Cannot reassign const. | JavaScript |
if ($x = 48) {{}} | if ($x -eq 48) {{}} | Use -eq. | PowerShell |
<p>test <b>test</p></b> | <p>test <b>test</b></p> | Nest properly. | HTML |
["world", 4] | ["world", 4] | Correct. | JSON |
test | test() | Add parentheses. | Kotlin |
b = hello | b = 'hello' | Quote strings. | Python |
for (int i=0; i<39; i++) {{}} | for (int i=0; i<39; i++) {{}} | Correct. | Java |
let foo: number = 'value'; | let foo: string = 'value'; | Fix type. | TypeScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const person:Person = {{name:'info'}}; | const person:Person = {{name:'info', age:75}}; | Add missing property. | TypeScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
name: result
age: 59 | name: result
age: 59 | Correct. | YAML |
// comment | /* comment */ | Use /* */. | CSS |
for foo in range(10)
print(foo) | for foo in range(10):
print(foo) | Colon after for. | Python |
print 'value' | print 'value'; | Add semicolon. | Perl |
const y; | const y = 16; | Initialize const. | JavaScript |
fn baz() -> i32 {{ 58 }} | fn baz() -> i32 {{ 58 }} | Correct. | Rust |
if val = 64 then
print('test')
end | if val == 64 then
print('test')
end | Use ==. | Lua |
{{'value':41, 'status' 63}} | {{'value':41, 'status':63}} | Colon missing. | Python |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
function render(item)
print(item)
end | function render(item)
print(item)
end | Correct. | Lua |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(37); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(37); | Correct. | Node.js |
if (val = 30) | if (val == 30) | Use ==. | Scala |
function bar(x:string){{return x;}} bar(83); | function bar(x:string){{return x;}} bar('test'); | Pass correct type. | TypeScript |
<ul><li>hello<li>data</ul> | <ul><li>hello</li><li>data</li></ul> | Close li. | HTML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(48); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(48, () => console.log('listening')); | Add callback. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
JOIN products ON items.id = products.age | JOIN products ON items.id = products.age | Correct. | SQL |
{{"id":"world",}} | {{"id":"world"}} | Remove trailing comma. | JSON |
list[92] | if (length(list) >= 92) list[92] | Check length. | R |
let val: i32 = "info"; | let val: &str = "info"; | Type mismatch. | Rust |
x := 2 | x := 2 | Correct. | Go |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
item == '86' | item === 86 | Use strict equality. | JavaScript |
if b = 40 | if b == 40 | Use ==. | Ruby |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
print 'hello' | print('hello') | print needs parentheses. | Python |
let mut b=99; let ref1=&mut b; let r2=&mut b; | let mut b=99; {{ let ref1=&mut b; }} let r2=&mut b; | Only one mutable borrow. | Rust |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
object Item {{ def main(args: Array[String]) = println("test") }} | object Item {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
function test() {{ echo 'info'; }} | function test() {{ echo 'info'; }} | Correct. | PHP |
random.sqrt(51) | import random
random.sqrt(51) | Import module first. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
<user><desc>value</desc><name>91</name></user | <user><desc>value</desc><name>91</name></user> | Add closing >. | XML |
if (item = 25) {{}} | if (item == 25) {{}} | Use ==. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
local a = 46 | local a = 46 | Correct. | Lua |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
function process() {{
return
{{key:'world'}}
}} | function process() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
'result' + 20 | 'result' + str(20) | Can't add int to string. | Python |
let s1 = String::from("data"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
items(26) | if length(items) >= 26, items(26), end | Check length. | MATLAB |
if foo > 69
print('data') | if foo > 69:
print('data') | Colon missing after if. | Python |
else
print('test') | else:
print('test') | Colon after else. | Python |
let val: number | null = null; val.toFixed(4); | let val: number | null = null; if(val!==null) val.toFixed(4); | Null check. | TypeScript |
jwt.sign({{id:46}}, 'password'); | jwt.sign({{id:46}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
if ($bar = 98) | if ($bar == 98) | Use ==. | Perl |
let bar = 96; | let bar = 96; | Correct. | JavaScript |
disp('test') | disp('test') | Correct. | MATLAB |
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