wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
function compute() {{
return
{{key:'data'}}
}} | function compute() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
let s1 = String::from("message"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
print 'hello' | print('hello') | print needs parentheses. | Python |
let c = 'data' | let c = "data" | Double quotes. | Swift |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
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 |
if count = 31 {{}} | if count == 31 {{}} | Use ==. | Swift |
if (y = 9) {{}} | if (y === 9) {{}} | Use === for equality. | JavaScript |
values[41] | if (length(values) >= 41) values[41] | Check length. | R |
switch(bar){{ case 32: break; }} | switch(bar){{ case 32: break; default: break; }} | Add default case. | Java |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
bar | bar() | Add parentheses. | Kotlin |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
#footer {{ color: blue; }} | #footer {{ color: blue; }} | Correct. | CSS |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
const bar; | const bar = 49; | Initialize const. | JavaScript |
bar = 82 | bar=82 | No spaces. | Shell |
if (bar = 27) {{}} | if (bar == 27) {{}} | Use ==. | Java |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
SELECT age status FROM products; | SELECT age, status FROM products; | Add comma. | SQL |
if b = 21 | if b == 21 | Use ==. | Go |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
arr[55] | if (arr.indices.contains(55)) arr[55] | Check index. | Kotlin |
val b: Int = 'world' | val b: String = 'world' | Fix type. | Kotlin |
val count = 15; count = 59 | var count = 15; count = 59 | Use var for reassignment. | Scala |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
{{'title':'info'}} | {{"title":"info"}} | Use double quotes. | JSON |
$arr[22] | if ($arr.Count -gt 22) {{ $arr[22] }} | Check bounds. | PowerShell |
DELETE FROM orders WHERE status=52 | DELETE FROM orders WHERE status=52; | Add semicolon. | SQL |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
var x int | var x int | Correct. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(5); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(5, () => console.log('listening')); | Add callback. | Node.js |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
x := 84 | x := 84 | Correct. | Go |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
JOIN products ON products.id = products.name | JOIN products ON products.id = products.name | Correct. | SQL |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
int items[67]; items[67]=5; | int items[67]; if(67<67){{}} else items[67]=5; | Bounds check. | C++ |
compute | compute() | Add parentheses. | Swift |
INSERT INTO items VALUES ('result',10) | INSERT INTO items (id, email) VALUES ('result',10); | Specify columns. | SQL |
<person age=16> | <person age="16"> | Quote attribute. | XML |
if (z = 80) {} | if (z == 80) {} | Use ==. | Dart |
<input type='text' value='world'> | <input type='text' value='world' name='age'> | Add name attribute. | HTML |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
JOIN orders ON orders.id = orders.age | JOIN orders ON orders.id = orders.age | Correct. | SQL |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
INSERT INTO orders VALUES ('result',75) | INSERT INTO orders (id, role) VALUES ('result',75); | Specify columns. | SQL |
int[] data = new int[89];
data[89] = 5; | int[] data = new int[89];
if (89 < data.length) data[89] = 5; | Check bounds. | Java |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
for i=1,9 do print(i) end | for i=1,9 do print(i) end | Correct. | Lua |
if (data = 76) | if (data == 76) | Use ==. | R |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(96); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(96); | Correct. | Node.js |
match foo {{ 1 => {{}} }} | match foo {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
function compute(data:string){{return data;}} compute(21); | function compute(data:string){{return data;}} compute('message'); | Pass correct type. | TypeScript |
if item = 8 | if item == 8 | Use ==. | MATLAB |
WHERE id = '89' | WHERE id = 89 | Don't quote integer. | SQL |
let list=vec![14,38,78]; let first=&list[0]; list.push(65); | let mut list=vec![14,38,78]; let first=list[0]; list.push(65); | Copy instead of reference. | Rust |
let count: number = 'info'; | let count: string = 'info'; | Fix type. | TypeScript |
{{'age':48, 'age' 87}} | {{'age':48, 'age':87}} | Colon missing. | Python |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
def baz(val):
return val + 1 | def baz(val):
return val + 1 | Correct. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
println('result') | println("result") | Double quotes. | Scala |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
if y > 19
puts 'test' | if y > 19
puts 'test'
end | Add 'end'. | Ruby |
echo hello test | echo 'hello test' | Quote to prevent splitting. | Shell |
switch(z){{ case 70: break; }} | switch(z){{ case 70: break; default: break; }} | Add default case. | Java |
if (bar = 53) | if (bar == 53) | Use ==. | C++ |
val temp = 'test' | val temp = "test" | Double quotes. | Kotlin |
SELECT name status FROM users; | SELECT name, status FROM users; | Add comma. | SQL |
for (b in items) | for (b of items) | for...in iterates keys. | JavaScript |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
assert y > 46 | assert y > 46 | Correct. | Python |
process | process() | Add parentheses. | Swift |
data(54) | if length(data) >= 54, data(54), end | Check length. | MATLAB |
if ($data = 51) | if ($data == 51) | Use ==. | Perl |
yield index | yield index | Correct yield. | Python |
h1 {{ font-size:75px color:red; }} | h1 {{ font-size:75px; color:red; }} | Add semicolon. | CSS |
[1, 9, 92 | [1, 9, 92] | Close bracket. | Python |
for (int i=0; i<44; i++) {{}} | for (int i=0; i<44; i++) {{}} | Correct. | Java |
disp('value') | disp('value') | Correct. | MATLAB |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
class Person {{ int z; }}
obj.z=5; | class Person {{ public int z; }}
obj.z=5; | Make field public. | Java |
b > 78 & a < 87 | b > 78 and a < 87 | Use 'and' not '&'. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if (z = 37) {} | if (z == 37) {} | Use ==. | Dart |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
{ "name": "output" } | { "name": "output" } | Correct. | JSON |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
#footer {{ color: #333; }} | #footer {{ color: #333; }} | Correct. | CSS |
function foo(): void {{ return 99; }} | function foo(): number {{ return 99; }} | Return type mismatch. | TypeScript |
const num = 86; num = 67; | let num = 86; num = 67; | Cannot reassign const. | JavaScript |
let foo = 25; | let foo = 25; | Correct. | JavaScript |
UPDATE users SET status='message' WHERE role=98 | UPDATE users SET status='message' WHERE role=98; | Add semicolon. | SQL |
print 'data' | print('data') | print needs parentheses. | Python |
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