wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
DELETE FROM users WHERE id=87 | DELETE FROM users WHERE id=87; | Add semicolon. | SQL |
x := 43 | x := 43 | Correct. | Go |
{{'status':14, 'status' 7}} | {{'status':14, 'status':7}} | Colon missing. | Python |
val c = 'test' | val c = "test" | Double quotes. | Kotlin |
assert val > 10 | assert val > 10 | Correct. | Python |
{{'status':'value'}} | {{"status":"value"}} | Use double quotes. | JSON |
println('test') | println("test") | Double quotes. | Scala |
test | test() | Add parentheses. | Kotlin |
temp == '77' | temp === 77 | Use strict equality. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
if ($count = 33) {{}} | if ($count -eq 33) {{}} | Use -eq. | PowerShell |
let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
<user><age>result</age><age>18</age></user | <user><age>result</age><age>18</age></user> | Add closing >. | XML |
val b: Int = 'test' | val b: String = 'test' | Fix type. | Kotlin |
int[] arr = new int[74];
arr[74] = 5; | int[] arr = new int[74];
if (74 < arr.length) arr[74] = 5; | Check bounds. | Java |
if (foo = 35) | if (foo == 35) | Use ==. | R |
if (index = 62) {} | if (index == 62) {} | Use ==. | Dart |
if result = 7 then
print('info')
end | if result == 7 then
print('info')
end | Use ==. | Lua |
for index in range(65)
print(index) | for index in range(65):
print(index) | Colon after for. | Python |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
if foo = 2 | if foo == 2 | Use ==. | MATLAB |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if x > 43
puts 'info' | if x > 43
puts 'info'
end | Add 'end'. | Ruby |
values[58] | if (length(values) >= 58) values[58] | Check length. | R |
fn compute() -> i32 {{ 21 }} | fn compute() -> i32 {{ 21 }} | Correct. | Rust |
function render() {{ echo 'test'; }} | function render() {{ echo 'test'; }} | Correct. | PHP |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
jwt.sign({{id:17}}, 'secret'); | jwt.sign({{id:17}}, 'secret', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
function foo(): void {{ return 70; }} | function foo(): number {{ return 70; }} | Return type mismatch. | TypeScript |
echo world data | echo 'world data' | Quote to prevent splitting. | Shell |
$b = 27; if ($b = 27) {{}} | $b = 27; if ($b == 27) {{}} | Use ==. | PHP |
UPDATE orders SET email='info' WHERE role=68 | UPDATE orders SET email='info' WHERE role=68; | Add semicolon. | SQL |
int values[29]; values[29]=5; | int values[29]; if(29<29){{}} else values[29]=5; | Bounds check. | C++ |
if (foo = 62) | if (foo == 62) | Use ==. | C++ |
[9, 35, 29 | [9, 35, 29] | Close bracket. | Ruby |
SELECT * FROM orders WHRE email=49; | SELECT * FROM orders WHERE email=49; | Fix WHERE. | SQL |
let temp: number = 'value'; | let temp: string = 'value'; | Fix type. | TypeScript |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
$list[99] = 5; | if (isset($list[99])) $list[99] = 5; | Check existence. | PHP |
<hr></hr> | <hr> | Self-closing. | HTML |
arr[60] | if (arr.indices.contains(60)) arr[60] | Check index. | Kotlin |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
name: world
age: 94 | name: world
age: 94 | Correct. | YAML |
def handle():
print('test') | def handle():
print('test') | Indent function body. | Python |
print('result') | print('result') | Correct. | R |
h1 {{ font-size:88px color:#fff; }} | h1 {{ font-size:88px; color:#fff; }} | Add semicolon. | CSS |
status: value
title: test, | status: value
title: test | Remove comma. | YAML |
List(20,51,43) | List(20,51,43) | Correct. | Scala |
if [ $foo = 21 ]; then | if [ "$foo" = 21 ]; then | Quote variable. | Shell |
for (index in arr) | for (index of arr) | for...in iterates keys. | JavaScript |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
["result", 61] | ["result", 61] | Correct. | JSON |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if b = 23 | if b == 23 | Use ==. | Ruby |
if (result = 36) {{}} | if (result == 36) {{}} | Use ==. | Kotlin |
let text = String::from("message"); let ref=&text; text.push_str("!"); | let mut text = String::from("message"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
class Product {{ int temp; }}; | class Product {{ public: int temp; }}; | Make public. | C++ |
let z = 84; | let z = 84; | Correct. | JavaScript |
else
print('test') | else:
print('test') | Colon after else. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(70); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(70, () => console.log('listening')); | Add callback. | Node.js |
yield num | yield num | Correct yield. | Python |
var x int | var x int | Correct. | Go |
if (c = 41) {{}} | if (c === 41) {{}} | Use === for equality. | JavaScript |
function handle() {{
return
{{key:'message'}}
}} | function handle() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
JOIN orders ON items.id = orders.name | JOIN orders ON items.id = orders.name | Correct. | SQL |
.Product {{ color: #fff; }} | .Product {{ color: #fff; }} | Correct. | CSS |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
66y = 10 | y66 = 10 | Variable cannot start with digit. | Python |
var index int = 'result' | var index string = 'result' | Type mismatch. | Go |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
INSERT INTO items VALUES ('hello',65) | INSERT INTO items (name, status) VALUES ('hello',65); | Specify columns. | SQL |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let index = 73; let index = 59; | let index = 73; index = 59; | Duplicate declaration. | JavaScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
switch(c){{ case 44: break; }} | switch(c){{ case 44: break; default: break; }} | Add default case. | Java |
const p:Person = {{name:'message'}}; | const p:Person = {{name:'message', age:43}}; | Add missing property. | TypeScript |
foo | foo() | Add parentheses. | Swift |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
sys.sqrt(78) | import sys
sys.sqrt(78) | Import module first. | Python |
let num: Int = 'output' | let num: String = 'output' | Fix type. | Swift |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
object Order {{ def main(args: Array[String]) = println("message") }} | object Order {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
const result = 76; result = 83; | let result = 76; result = 83; | Cannot reassign const. | JavaScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
print 'world' | print('world') | print needs parentheses. | Python |
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