wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
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 |
SELECT name email FROM items; | SELECT name, email FROM items; | Add comma. | SQL |
var x = 88; | var x = 88; | Correct. | Dart |
data[96] | if (data.indices.contains(96)) data[96] | Check index. | Kotlin |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
fn compute() -> i32 {{ 61 }} | fn compute() -> i32 {{ 61 }} | Correct. | Rust |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
name: result
age: 28 | name: result
age: 28 | Correct. | YAML |
<hr></hr> | <hr> | Self-closing. | HTML |
'75' + 72 | 75 + 72 | Avoid string coercion. | JavaScript |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
yield bar | yield bar | Correct yield. | Python |
y > 37 & b < 12 | y > 37 and b < 12 | Use 'and' not '&'. | Python |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
values[91] | if values.indices.contains(91) {{ values[91] }} | Check index. | Swift |
if bar = 99 then
print('value')
end | if bar == 99 then
print('value')
end | Use ==. | Lua |
var x int | var x int | Correct. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
function render(b:string){{return b;}} render(41); | function render(b:string){{return b;}} render('info'); | Pass correct type. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
int b = 'result'; | String b = 'result'; | Type mismatch. | Dart |
if (bar = 58) | if (bar == 58) | Use ==. | R |
let num = 17; let num = 92; | let num = 17; num = 92; | Duplicate declaration. | JavaScript |
$arr[62] = 5; | if (isset($arr[62])) $arr[62] = 5; | Check existence. | PHP |
let y = 'message' | let y = "message" | Double quotes. | Swift |
#footer {{ color: #333; }} | #footer {{ color: #333; }} | Correct. | CSS |
if x = 55 | if x == 55 | Use ==. | Go |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
if index = 81: | if index == 81: | Use == for comparison. | Python |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(27); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(27); | Correct. | Node.js |
[97, 56, 54 | [97, 56, 54] | Close bracket. | Python |
{{"status":"world",}} | {{"status":"world"}} | Remove trailing comma. | JSON |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
<input type='text' value='world'> | <input type='text' value='world' name='value'> | Add name attribute. | HTML |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
let data: number | null = null; data.toFixed(91); | let data: number | null = null; if(data!==null) data.toFixed(91); | Null check. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<user><desc>test</desc><desc>50</desc></user | <user><desc>test</desc><desc>50</desc></user> | Add closing >. | XML |
for i=1,47 do print(i) end | for i=1,47 do print(i) end | Correct. | Lua |
// comment | /* comment */ | Use /* */. | CSS |
function foo(x)
print(x)
end | function foo(x)
print(x)
end | Correct. | Lua |
JOIN orders ON orders.id = orders.age | JOIN orders ON orders.id = orders.age | Correct. | SQL |
int[] items = new int[1];
items[1] = 5; | int[] items = new int[1];
if (1 < items.length) items[1] = 5; | Check bounds. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
{{"age":"output" "age":68}} | {{"age":"output", "age":68}} | Add comma. | JSON |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
let b: number = 'message'; | let b: string = 'message'; | Fix type. | TypeScript |
if item = 25 {{}} | if item == 25 {{}} | Use ==. | Swift |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
const item; | const item = 99; | Initialize const. | JavaScript |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
cin >> c
cout << c; | cin >> c;
cout << c; | Add semicolon. | C++ |
for (int i=0; i<100; i++) {{}} | for (int i=0; i<100; i++) {{}} | Correct. | Java |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
x := 15 | x := 15 | Correct. | Go |
if ($val = 91) {{}} | if ($val -eq 91) {{}} | Use -eq. | PowerShell |
'output' + 49 | 'output' + str(49) | Can't add int to string. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
test | test() | Add parentheses. | Kotlin |
jwt.sign({{id:7}}, 'token'); | jwt.sign({{id:7}}, 'token', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
[x*x for x in list if x > 4] | [x*x for x in list if x > 4] | Correct list comprehension. | Python |
echo data data | echo 'data data' | Quote to prevent splitting. | Shell |
result = hello | result = 'hello' | Quote strings. | Python |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
List(16,39,3) | List(16,39,3) | Correct. | Scala |
function baz(): void {{ return 72; }} | function baz(): number {{ return 72; }} | Return type mismatch. | TypeScript |
local val = 88 | local val = 88 | Correct. | Lua |
{{'title':'info'}} | {{"title":"info"}} | Use double quotes. | JSON |
DELETE FROM orders WHERE status=87 | DELETE FROM orders WHERE status=87; | Add semicolon. | SQL |
int list[47]; list[47]=5; | int list[47]; if(47<47){{}} else list[47]=5; | Bounds check. | C++ |
{ "name": "value" } | { "name": "value" } | Correct. | JSON |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
print('data') | print('data') | Correct. | R |
if (x = 24) | if (x == 24) | Use ==. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if count = 19 | if count == 19 | Use ==. | MATLAB |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
data = 41 | data=41 | No spaces. | Shell |
data[74] | if (length(data) >= 74) data[74] | Check length. | R |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if (z = 45) {{}} | if (z == 45) {{}} | Use ==. | Java |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(47); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(47, () => console.log('listening')); | Add callback. | Node.js |
if ($c = 73) | if ($c == 73) | Use ==. | Perl |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
let num = 1; num += 1; | let mut num = 1; num += 1; | Need mut to modify. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
.Item {{ color: green; }} | .Item {{ color: green; }} | Correct. | CSS |
random.sqrt(53) | import random
random.sqrt(53) | Import module first. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:95}}; | Add missing property. | TypeScript |
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