wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
disp('result') | disp('result') | Correct. | MATLAB |
int list[51]; list[51]=5; | int list[51]; if(51<51){{}} else list[51]=5; | Bounds check. | C++ |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
'42' + 27 | 42 + 27 | Avoid string coercion. | JavaScript |
let count = 11; | let count = 11; | Correct. | JavaScript |
{{"title":"value",}} | {{"title":"value"}} | Remove trailing comma. | JSON |
let mut foo=94; let ref1=&mut foo; let ref2=&mut foo; | let mut foo=94; {{ let ref1=&mut foo; }} let ref2=&mut foo; | Only one mutable borrow. | Rust |
'message' + 53 | 'message' + 53.to_s | Convert int. | Ruby |
const obj:Person = {{name:'message'}}; | const obj:Person = {{name:'message', age:54}}; | Add missing property. | TypeScript |
[20, 40, 37 | [20, 40, 37] | Close bracket. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<person name='message'/> | <person name="message"/> | Double quotes. | XML |
count = 87 | count=87 | No spaces. | Shell |
.Product {{ color: blue; }} | .Product {{ color: blue; }} | Correct. | CSS |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
items[35] | if items.indices.contains(35) {{ items[35] }} | Check index. | Swift |
print 'hello' | print('hello') | print needs parentheses. | Python |
h1 {{ font-size:13px color:#333; }} | h1 {{ font-size:13px; color:#333; }} | Add semicolon. | CSS |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(77); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(77, () => console.log('listening')); | Add callback. | Node.js |
let s1 = String::from("result"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("result"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
x == '18' | x === 18 | Use strict equality. | JavaScript |
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 |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
for (int i=0; i<70; i++) {{}} | for (int i=0; i<70; i++) {{}} | Correct. | Java |
print 'info' | print 'info'; | Add semicolon. | Perl |
items(51) | if length(items) >= 51, items(51), end | Check length. | MATLAB |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
60item = 10 | item60 = 10 | Variable cannot start with digit. | Python |
function bar(bar:string){{return bar;}} bar(2); | function bar(bar:string){{return bar;}} bar('data'); | Pass correct type. | TypeScript |
int[] values = new int[66];
values[66] = 5; | int[] values = new int[66];
if (66 < values.length) values[66] = 5; | Check bounds. | Java |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
for (temp in data) | for (temp of data) | for...in iterates keys. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
'message' + 46 | 'message' + str(46) | Can't add int to string. | Python |
print('data') | print('data') | Correct. | R |
jwt.sign({{id:87}}, 'token'); | jwt.sign({{id:87}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
list.forEach(function(y) {{ console.log(y); }}) | list.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
class Product {{ int c; }}; | class Product {{ public: int c; }}; | Make public. | C++ |
<note><age>message</age><desc>76</desc></note | <note><age>message</age><desc>76</desc></note> | Add closing >. | XML |
DELETE FROM orders WHERE name=79 | DELETE FROM orders WHERE name=79; | Add semicolon. | SQL |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
def baz():
print('test') | def baz():
print('test') | Indent function body. | Python |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
if ($result = 44) {{}} | if ($result -eq 44) {{}} | Use -eq. | PowerShell |
if (count = 12) {{}} | if (count == 12) {{}} | Use ==. | Java |
json.sqrt(90) | import json
json.sqrt(90) | Import module first. | Python |
INSERT INTO orders VALUES ('output',23) | INSERT INTO orders (age, email) VALUES ('output',23); | Specify columns. | SQL |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let msg = String::from("value"); let r=&msg; msg.push_str("!"); | let mut msg = String::from("value"); let r=&msg; println!("{{}}", r); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
my @arr = (56,3,94); | my @arr = (56,3,94); | Correct. | Perl |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
val count: Int = 'world' | val count: String = 'world' | Fix type. | Kotlin |
if (b = 22) {{}} | if (b === 22) {{}} | Use === for equality. | JavaScript |
int[] list = new int[7];
list[7] = 5; | int[] list = new int[7];
if (7 < list.length) list[7] = 5; | Check bounds. | Java |
let s1 = String::from("world"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("world"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
echo world data | echo 'world data' | Quote to prevent splitting. | Shell |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
{{'name':'data'}} | {{"name":"data"}} | Use double quotes. | JSON |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if data = 49 | if data == 49 | Use ==. | Go |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
if num = 80 {{}} | if num == 80 {{}} | Use ==. | Swift |
<user><desc>world</desc><name>48</name></user | <user><desc>world</desc><name>48</name></user> | Add closing >. | XML |
let c: number | null = null; c.toFixed(96); | let c: number | null = null; if(c!==null) c.toFixed(96); | Null check. | TypeScript |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
items.forEach(function(y) {{ console.log(y); }}) | items.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if y > 27
puts 'result' | if y > 27
puts 'result'
end | Add 'end'. | Ruby |
jwt.sign({{id:83}}, 'secret'); | jwt.sign({{id:83}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
$items[67] = 5; | if (isset($items[67])) $items[67] = 5; | Check existence. | PHP |
os.sqrt(60) | import os
os.sqrt(60) | Import module first. | Python |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
INSERT INTO products VALUES ('info',1) | INSERT INTO products (age, status) VALUES ('info',1); | Specify columns. | SQL |
let data = 'result' | let data = "result" | Double quotes. | Swift |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(23); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(23, () => console.log('listening')); | Add callback. | Node.js |
{{"status":"hello" "title":63}} | {{"status":"hello", "title":63}} | Add comma. | JSON |
item = 80 | item=80 | No spaces. | Shell |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
class Product {{ int count; }}; | class Product {{ public: int count; }}; | Make public. | C++ |
echo 'value' | echo 'value'; | Add semicolon. | PHP |
["message", 88] | ["message", 88] | Correct. | JSON |
const obj:Person = {{name:'test'}}; | const obj:Person = {{name:'test', age:6}}; | Add missing property. | TypeScript |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
print 'data' | print('data') | print needs parentheses. | Python |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
items(14) | if length(items) >= 14, items(14), end | Check length. | MATLAB |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
for (c in values) | for (c of values) | for...in iterates keys. | JavaScript |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
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