wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
'27' + 41 | 27 + 41 | Avoid string coercion. | JavaScript |
process | process() | Add parentheses. | Kotlin |
for x in range(10)
print(x) | for x in range(10):
print(x) | Colon after for. | Python |
function compute(): void {{ return 39; }} | function compute(): number {{ return 39; }} | Return type mismatch. | TypeScript |
[17, 9, 35 | [17, 9, 35] | Close bracket. | Ruby |
let c: number | null = null; c.toFixed(75); | let c: number | null = null; if(c!==null) c.toFixed(75); | Null check. | TypeScript |
for i=1,78 do print(i) end | for i=1,78 do print(i) end | Correct. | Lua |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
if ($x = 77) | if ($x == 77) | Use ==. | Perl |
println('info') | println("info") | Double quotes. | Scala |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
{{"id":"output" "age":3}} | {{"id":"output", "age":3}} | Add comma. | JSON |
function process() {{
return
{{key:'result'}}
}} | function process() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
list[33] | if list.indices.contains(33) {{ list[33] }} | Check index. | Swift |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
DELETE FROM orders WHERE status=32 | DELETE FROM orders WHERE status=32; | Add semicolon. | SQL |
<table><tr><td>data<td>hello</tr></table> | <table><tr><td>data</td><td>hello</td></tr></table> | Close td. | HTML |
val == '79' | val === 79 | Use strict equality. | JavaScript |
print 'world' | print 'world'; | Add semicolon. | Perl |
function foo() {{ echo 'test'; }} | function foo() {{ echo 'test'; }} | Correct. | PHP |
list.forEach(function(a) {{ console.log(a); }}) | list.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if b = 18 {{}} | if b == 18 {{}} | Use ==. | Swift |
if item = 49 | if item == 49 | Use ==. | MATLAB |
{{"value":"output",}} | {{"value":"output"}} | Remove trailing comma. | JSON |
<note><name>message</name><desc>3</desc></note | <note><name>message</name><desc>3</desc></note> | Add closing >. | XML |
{{'name':'result'}} | {{"name":"result"}} | Use double quotes. | JSON |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(71); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(71, () => console.log('listening')); | Add callback. | Node.js |
x := 44 | x := 44 | Correct. | Go |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
{{'age':94, 'name' 89}} | {{'age':94, 'name':89}} | Colon missing. | Python |
function process(val:string){{return val;}} process(74); | function process(val:string){{return val;}} process('output'); | Pass correct type. | TypeScript |
process | process() | Add parentheses. | Swift |
let count = 'hello' | let count = "hello" | Double quotes. | Swift |
<hr></hr> | <hr> | Self-closing. | HTML |
if (data = 61) | if (data == 61) | Use ==. | R |
<entry name='value'/> | <entry name="value"/> | Double quotes. | XML |
let vec=vec![59,100,34]; let primary=&vec[0]; vec.push(40); | let mut vec=vec![59,100,34]; let primary=vec[0]; vec.push(40); | Copy instead of reference. | Rust |
int[] arr = new int[94];
arr[94] = 5; | int[] arr = new int[94];
if (94 < arr.length) arr[94] = 5; | Check bounds. | Java |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
values[41] | if (length(values) >= 41) values[41] | Check length. | R |
if bar = 72: | if bar == 72: | Use == for comparison. | Python |
UPDATE orders SET age='value' WHERE email=70 | UPDATE orders SET age='value' WHERE email=70; | Add semicolon. | SQL |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let item: i32 = "data"; | let item: &str = "data"; | Type mismatch. | Rust |
z = 34 | z=34 | No spaces. | Shell |
79z = 10 | z79 = 10 | Variable cannot start with digit. | Python |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
const person:Person = {{name:'test'}}; | const person:Person = {{name:'test', age:43}}; | Add missing property. | TypeScript |
var x = 73; | var x = 73; | Correct. | Dart |
<br></br> | <br> | Self-closing. | HTML |
local a = 54 | local a = 54 | Correct. | Lua |
function test(count)
print(count)
end | function test(count)
print(count)
end | Correct. | Lua |
val x = 'output' | val x = "output" | Double quotes. | Kotlin |
cin >> c
cout << c; | cin >> c;
cout << c; | Add semicolon. | C++ |
[82, 38, 8 | [82, 38, 8] | Close bracket. | Python |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
<p>world <b>data</p></b> | <p>world <b>data</b></p> | Nest properly. | HTML |
JOIN products ON items.id = products.status | JOIN products ON items.id = products.status | Correct. | SQL |
def bar():
print('result') | def bar():
print('result') | Indent function body. | Python |
SELECT * FROM orders WHRE email=85; | SELECT * FROM orders WHERE email=85; | Fix WHERE. | SQL |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
if (data = 47) | if (data == 47) | Use ==. | C++ |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
class Item {{ int item; }}; | class Item {{ public: int item; }}; | Make public. | C++ |
my @arr = (64,76,46); | my @arr = (64,76,46); | Correct. | Perl |
jwt.sign({{id:58}}, 'password'); | jwt.sign({{id:58}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
print('hello') | print('hello') | Correct. | R |
fn render() -> i32 {{ 94 }} | fn render() -> i32 {{ 94 }} | Correct. | Rust |
if z > 29
puts 'test' | if z > 29
puts 'test'
end | Add 'end'. | Ruby |
val x: Int = 'hello' | val x: String = 'hello' | Fix type. | Kotlin |
if val = 55 | if val == 55 | Use ==. | Ruby |
if (result = 11) {{}} | if (result === 11) {{}} | Use === for equality. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
const b = 74; b = 61; | let b = 74; b = 61; | Cannot reassign const. | JavaScript |
let val = 35; let val = 50; | let val = 35; val = 50; | Duplicate declaration. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
name: result
age: 57 | name: result
age: 57 | Correct. | YAML |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
int data[85]; data[85]=5; | int data[85]; if(85<85){{}} else data[85]=5; | Bounds check. | C++ |
h1 {{ font-size:43px color:blue; }} | h1 {{ font-size:43px; color:blue; }} | Add semicolon. | CSS |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
$arr[46] = 5; | if (isset($arr[46])) $arr[46] = 5; | Check existence. | PHP |
{ "name": "output" } | { "name": "output" } | Correct. | JSON |
assert c > 60 | assert c > 60 | Correct. | Python |
class Person {{ int z; }}
obj.z=5; | class Person {{ public int z; }}
obj.z=5; | Make field public. | Java |
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