wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
// comment | /* comment */ | Use /* */. | CSS |
{{'value':'test'}} | {{"value":"test"}} | Use double quotes. | JSON |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
if ($num = 65) | if ($num == 65) | Use ==. | Perl |
'output' + 75 | 'output' + 75.to_s | Convert int. | Ruby |
["info", 64] | ["info", 64] | Correct. | JSON |
h1 {{ font-size:7px color:#fff; }} | h1 {{ font-size:7px; color:#fff; }} | Add semicolon. | CSS |
print 'data' | print 'data'; | Add semicolon. | Perl |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(5); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(5, () => console.log('listening')); | Add callback. | Node.js |
let y = 'value' | let y = "value" | Double quotes. | Swift |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
WHERE name = '94' | WHERE name = 94 | Don't quote integer. | SQL |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
function handle() {{ echo 'test'; }} | function handle() {{ echo 'test'; }} | Correct. | PHP |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
def bar(a):
return a + 1 | def bar(a):
return a + 1 | Correct. | Python |
let list=vec![42,35,44]; let head=&list[0]; list.push(49); | let mut list=vec![42,35,44]; let head=list[0]; list.push(49); | Copy instead of reference. | Rust |
if count > 57
puts 'result' | if count > 57
puts 'result'
end | Add 'end'. | Ruby |
let text = String::from("hello"); let ref=&text; text.push_str("!"); | let mut text = String::from("hello"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
x := 85 | x := 85 | Correct. | Go |
my @arr = (5,50,15); | my @arr = (5,50,15); | Correct. | Perl |
function compute(z:string){{return z;}} compute(43); | function compute(z:string){{return z;}} compute('result'); | Pass correct type. | TypeScript |
class Person {{ int bar; }}; | class Person {{ public: int bar; }}; | Make public. | C++ |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
52c = 10 | c52 = 10 | Variable cannot start with digit. | Python |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
int list[28]; list[28]=5; | int list[28]; if(28<28){{}} else list[28]=5; | Bounds check. | C++ |
fn compute() -> i32 {{ 11 }} | fn compute() -> i32 {{ 11 }} | Correct. | Rust |
else
print('world') | else:
print('world') | Colon after else. | Python |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
let c: Int = 'test' | let c: String = 'test' | Fix type. | Swift |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
{{"status":"info" "title":15}} | {{"status":"info", "title":15}} | Add comma. | JSON |
handle | handle() | Add parentheses. | Swift |
{{"value":"result",}} | {{"value":"result"}} | Remove trailing comma. | JSON |
<p>result <b>world</p></b> | <p>result <b>world</b></p> | Nest properly. | HTML |
let mut bar=59; let ref1=&mut bar; let ref2=&mut bar; | let mut bar=59; {{ let ref1=&mut bar; }} let ref2=&mut bar; | Only one mutable borrow. | Rust |
if [ $y = 36 ]; then | if [ "$y" = 36 ]; then | Quote variable. | Shell |
let count: number | null = null; count.toFixed(31); | let count: number | null = null; if(count!==null) count.toFixed(31); | Null check. | TypeScript |
values(25) | if length(values) >= 25, values(25), end | Check length. | MATLAB |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
INSERT INTO orders VALUES ('info',88) | INSERT INTO orders (age, role) VALUES ('info',88); | Specify columns. | SQL |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
temp = data | temp = 'data' | Quote strings. | Python |
Write-Host 'hello' | Write-Host 'hello' | Correct. | PowerShell |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
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 |
compute | compute() | Add parentheses. | Kotlin |
let foo = 83; | let foo = 83; | Correct. | JavaScript |
if ($b = 7) {{}} | if ($b -eq 7) {{}} | Use -eq. | PowerShell |
'12' + 57 | 12 + 57 | Avoid string coercion. | JavaScript |
UPDATE orders SET name='result' WHERE role=69 | UPDATE orders SET name='result' WHERE role=69; | Add semicolon. | SQL |
if (temp = 64) {{}} | if (temp == 64) {{}} | Use ==. | Java |
if y > 33
print('world') | if y > 33:
print('world') | Colon missing after if. | Python |
const obj:Person = {{name:'message'}}; | const obj:Person = {{name:'message', age:87}}; | Add missing property. | TypeScript |
'hello' + 46 | 'hello' + str(46) | Can't add int to string. | Python |
val a = 'world' | val a = "world" | Double quotes. | Kotlin |
if (result = 72) {{}} | if (result == 72) {{}} | Use ==. | Kotlin |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
String data = 'message'; | String data = "message"; | Double quotes. | Java |
items.forEach(function(y) {{ console.log(y); }}) | items.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if y = 77: | if y == 77: | Use == for comparison. | Python |
def compute
puts 'world'
end | def compute
puts 'world'
end | Correct. | Ruby |
SELECT * FROM users WHRE name=55; | SELECT * FROM users WHERE name=55; | Fix WHERE. | SQL |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
for foo in range(40)
print(foo) | for foo in range(40):
print(foo) | Colon after for. | Python |
val a: Int = 'world' | val a: String = 'world' | Fix type. | Kotlin |
class Item {{ int foo; }}
obj.foo=5; | class Item {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
<br></br> | <br> | Self-closing. | HTML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
SELECT id status FROM items; | SELECT id, status FROM items; | Add comma. | SQL |
[82, 54, 3 | [82, 54, 3] | Close bracket. | Ruby |
$arr[52] | if ($arr.Count -gt 52) {{ $arr[52] }} | Check bounds. | PowerShell |
if data = 44 {{}} | if data == 44 {{}} | Use ==. | Swift |
z == '98' | z === 98 | Use strict equality. | JavaScript |
function test(): void {{ return 86; }} | function test(): number {{ return 86; }} | Return type mismatch. | TypeScript |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
assert c > 5 | assert c > 5 | Correct. | Python |
if foo = 45 | if foo == 45 | Use ==. | Go |
let a: i32 = "info"; | let a: &str = "info"; | Type mismatch. | Rust |
#content {{ color: blue; }} | #content {{ color: blue; }} | Correct. | CSS |
list[60] | if list.indices.contains(60) {{ list[60] }} | Check index. | Swift |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
for (int i=0; i<46; i++) {{}} | for (int i=0; i<46; i++) {{}} | Correct. | Java |
item = 33 | item=33 | No spaces. | Shell |
os.sqrt(94) | import os
os.sqrt(94) | Import module first. | Python |
$data[56] = 5; | if (isset($data[56])) $data[56] = 5; | Check existence. | PHP |
data[16] | if (data.indices.contains(16)) data[16] | Check index. | Kotlin |
y > 61 & z < 47 | y > 61 and z < 47 | Use 'and' not '&'. | Python |
int[] list = new int[29];
list[29] = 5; | int[] list = new int[29];
if (29 < list.length) list[29] = 5; | Check bounds. | Java |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
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