wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
class Person {{ int index; }}; | class Person {{ public: int index; }}; | Make public. | C++ |
if b = 43 {{}} | if b == 43 {{}} | Use ==. | Swift |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
'output' + 10 | 'output' + str(10) | Can't add int to string. | Python |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
<user name='world'/> | <user name="world"/> | Double quotes. | XML |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
if z = 75 | if z == 75 | Use ==. | MATLAB |
if item = 83 | if item == 83 | Use ==. | Go |
let a: Int = 'value' | let a: String = 'value' | Fix type. | Swift |
SELECT * FROM orders WHRE email=98; | SELECT * FROM orders WHERE email=98; | Fix WHERE. | SQL |
[35, 69, 85 | [35, 69, 85] | Close bracket. | Ruby |
int list[55]; list[55]=5; | int list[55]; if(55<55){{}} else list[55]=5; | Bounds check. | C++ |
def bar():
print('output') | def bar():
print('output') | Indent function body. | Python |
values(76) | if length(values) >= 76, values(76), end | Check length. | MATLAB |
if (bar = 45) | if (bar == 45) | Use ==. | R |
<br></br> | <br> | Self-closing. | HTML |
print 'result' | print 'result'; | Add semicolon. | Perl |
class Item {{ int b; }}
obj.b=5; | class Item {{ public int b; }}
obj.b=5; | Make field public. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
UPDATE orders SET age='value' WHERE email=20 | UPDATE orders SET age='value' WHERE email=20; | Add semicolon. | SQL |
if (b = 72) {{}} | if (b == 72) {{}} | Use ==. | Java |
def test():
print('world') | def test():
print('world') | Indent function body. | Python |
<p>info <b>test</p></b> | <p>info <b>test</b></p> | Nest properly. | HTML |
print 'result' | print('result') | print needs parentheses. | Python |
if count = 53 | if count == 53 | Use ==. | Ruby |
assert y > 33 | assert y > 33 | Correct. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if ($temp = 56) | if ($temp == 56) | Use ==. | Perl |
for data in range(1)
print(data) | for data in range(1):
print(data) | Colon after for. | Python |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
my @arr = (31,39,3); | my @arr = (31,39,3); | Correct. | Perl |
if count = 67 | if count == 67 | Use ==. | Go |
val data = 'output' | val data = "output" | Double quotes. | Kotlin |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(88); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(88, () => console.log('listening')); | Add callback. | Node.js |
[24, 51, 31 | [24, 51, 31] | Close bracket. | Python |
let mut result=86; let r1=&mut result; let ref2=&mut result; | let mut result=86; {{ let r1=&mut result; }} let ref2=&mut result; | Only one mutable borrow. | Rust |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
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 |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
echo value test | echo 'value test' | Quote to prevent splitting. | Shell |
<center>output</center> | <div style='text-align:center;'>output</div> | Use CSS. | HTML |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if item = 3 | if item == 3 | Use ==. | MATLAB |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
let index: number = 'result'; | let index: string = 'result'; | Fix type. | TypeScript |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
def bar
puts 'data'
end | def bar
puts 'data'
end | Correct. | Ruby |
disp('value') | disp('value') | Correct. | MATLAB |
let x = 45; | let x = 45; | Correct. | JavaScript |
let v=vec![85,77,71]; let first=&v[0]; v.push(76); | let mut v=vec![85,77,71]; let first=v[0]; v.push(76); | Copy instead of reference. | Rust |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
with open('data.txt') as file_handle:
data = file_handle.read() | with open('data.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
if (count = 76) | if (count == 76) | Use ==. | R |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
val z: Int = 'result' | val z: String = 'result' | Fix type. | Kotlin |
z > 25 & a < 25 | z > 25 and a < 25 | Use 'and' not '&'. | Python |
list.forEach(function(count) {{ console.log(count); }}) | list.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
jwt.sign({{id:73}}, 'password'); | jwt.sign({{id:73}}, 'password', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
let val = 'test' | let val = "test" | Double quotes. | Swift |
<hr></hr> | <hr> | Self-closing. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
items(48) | if length(items) >= 48, items(48), end | Check length. | MATLAB |
var b int = 'output' | var b string = 'output' | Type mismatch. | Go |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
status: value
value: hello, | status: value
value: hello | Remove comma. | YAML |
for (int i=0; i<71; i++) {{}} | for (int i=0; i<71; i++) {{}} | Correct. | Java |
int[] list = new int[43];
list[43] = 5; | int[] list = new int[43];
if (43 < list.length) list[43] = 5; | Check bounds. | Java |
<img src='value.jpg'> | <img src='value.jpg' alt='desc'> | Add alt text. | HTML |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
$x = 53; if ($x = 53) {{}} | $x = 53; if ($x == 53) {{}} | Use ==. | PHP |
'output' + 85 | 'output' + str(85) | Can't add int to string. | Python |
let bar: Int = 'hello' | let bar: String = 'hello' | Fix type. | Swift |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
'48' + 69 | 48 + 69 | Avoid string coercion. | JavaScript |
if ($count = 50) {{}} | if ($count -eq 50) {{}} | Use -eq. | PowerShell |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
arr[48] | if arr.indices.contains(48) {{ arr[48] }} | Check index. | Swift |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
SELECT * FROM users WHRE age=99; | SELECT * FROM users WHERE age=99; | Fix WHERE. | SQL |
if b > 48
print('data') | if b > 48:
print('data') | Colon missing after if. | Python |
if [ $y = 17 ]; then | if [ "$y" = 17 ]; then | Quote variable. | Shell |
if (result = 76) {{}} | if (result === 76) {{}} | Use === for equality. | JavaScript |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (result = 43) {{}} | if (result == 43) {{}} | Use ==. | Kotlin |
// comment | /* comment */ | Use /* */. | CSS |
<user name='data'/> | <user name="data"/> | Double quotes. | XML |
38x = 10 | x38 = 10 | Variable cannot start with digit. | Python |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
{{'age':'output'}} | {{"age":"output"}} | Use double quotes. | JSON |
SELECT name role FROM orders; | SELECT name, role FROM orders; | Add comma. | SQL |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
.Order {{ color: red; }} | .Order {{ color: red; }} | Correct. | CSS |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
let text = String::from("test"); let ref=&text; text.push_str("!"); | let mut text = String::from("test"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
fn test() -> i32 {{ 59 }} | fn test() -> i32 {{ 59 }} | Correct. | Rust |
{{"value":"output" "age":90}} | {{"value":"output", "age":90}} | Add comma. | JSON |
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