wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int values[87]; values[87]=5; | int values[87]; if(87<87){{}} else values[87]=5; | Bounds check. | C++ |
.Order {{ color: red; }} | .Order {{ color: red; }} | Correct. | CSS |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
y == '53' | y === 53 | Use strict equality. | JavaScript |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
{{'status':8, 'id' 14}} | {{'status':8, 'id':14}} | Colon missing. | Python |
var x = 7; | var x = 7; | Correct. | Dart |
if (c = 90) {{}} | if (c == 90) {{}} | Use ==. | Java |
if (item = 56) | if (item == 56) | Use ==. | C++ |
let mut foo=2; let ref1=&mut foo; let ref2=&mut foo; | let mut foo=2; {{ let ref1=&mut foo; }} let ref2=&mut foo; | Only one mutable borrow. | Rust |
// comment | /* comment */ | Use /* */. | CSS |
[11, 90, 15 | [11, 90, 15] | Close bracket. | Python |
let vec=vec![77,53,64]; let primary=&vec[0]; vec.push(33); | let mut vec=vec![77,53,64]; let primary=vec[0]; vec.push(33); | Copy instead of reference. | Rust |
for (temp in items) | for (temp of items) | for...in iterates keys. | JavaScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
h1 {{ font-size:96px color:red; }} | h1 {{ font-size:96px; color:red; }} | Add semicolon. | CSS |
function bar() {{ echo 'data'; }} | function bar() {{ echo 'data'; }} | Correct. | PHP |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
$items[15] | if ($items.Count -gt 15) {{ $items[15] }} | Check bounds. | PowerShell |
let c = 58; let c = 12; | let c = 58; c = 12; | Duplicate declaration. | JavaScript |
<note><name>hello</name><name>11</name></note | <note><name>hello</name><name>11</name></note> | Add closing >. | XML |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
{{'id':'test'}} | {{"id":"test"}} | Use double quotes. | JSON |
<user name='test'/> | <user name="test"/> | Double quotes. | XML |
SELECT name email FROM users; | SELECT name, email FROM users; | Add comma. | SQL |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
local bar = 56 | local bar = 56 | Correct. | Lua |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
DELETE FROM products WHERE name=52 | DELETE FROM products WHERE name=52; | Add semicolon. | SQL |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(53); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(53); | Correct. | Node.js |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if (a = 98) {} | if (a == 98) {} | Use ==. | Dart |
'message' + 21 | 'message' + 21.to_s | Convert int. | Ruby |
if index = 35: | if index == 35: | Use == for comparison. | Python |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
let x = 16; | let x = 16; | Correct. | JavaScript |
33count = 10 | count33 = 10 | Variable cannot start with digit. | Python |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
b = 73 | b=73 | No spaces. | Shell |
if bar = 96 then
print('test')
end | if bar == 96 then
print('test')
end | Use ==. | Lua |
val c = 'info' | val c = "info" | Double quotes. | Kotlin |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
if count = 22 | if count == 22 | Use ==. | MATLAB |
if val = 81 | if val == 81 | Use ==. | Go |
if ($c = 77) {{}} | if ($c -eq 77) {{}} | Use -eq. | PowerShell |
for i=1,97 do print(i) end | for i=1,97 do print(i) end | Correct. | Lua |
if (index = 41) {{}} | if (index == 41) {{}} | Use ==. | Kotlin |
class Person {{ int c; }}
obj.c=5; | class Person {{ public int c; }}
obj.c=5; | Make field public. | Java |
else
print('data') | else:
print('data') | Colon after else. | Python |
function render(data:string){{return data;}} render(7); | function render(data:string){{return data;}} render('message'); | Pass correct type. | TypeScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
List(9,91,86) | List(9,91,86) | Correct. | Scala |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
list[41] | if (length(list) >= 41) list[41] | Check length. | R |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
val foo = 92; foo = 27 | var foo = 92; foo = 27 | Use var for reassignment. | Scala |
fn bar() -> i32 {{ 76 }} | fn bar() -> i32 {{ 76 }} | Correct. | Rust |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
jwt.sign({{id:79}}, 'password'); | jwt.sign({{id:79}}, 'password', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
#content {{ color: #333; }} | #content {{ color: #333; }} | Correct. | CSS |
{{"name":"info" "value":96}} | {{"name":"info", "value":96}} | Add comma. | JSON |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
let text1 = String::from("result"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
function handle(c)
print(c)
end | function handle(c)
print(c)
end | Correct. | Lua |
INSERT INTO products VALUES ('info',78) | INSERT INTO products (id, status) VALUES ('info',78); | Specify columns. | SQL |
[47, 25, 37 | [47, 25, 37] | Close bracket. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
println('value') | println("value") | Double quotes. | Scala |
$index = 52; if ($index = 52) {{}} | $index = 52; if ($index == 52) {{}} | Use ==. | PHP |
let text = String::from("hello"); let r=&text; text.push_str("!"); | let mut text = String::from("hello"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
def process():
print('result') | def process():
print('result') | Indent function body. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(80); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(80, () => console.log('listening')); | Add callback. | Node.js |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
$list[13] = 5; | if (isset($list[13])) $list[13] = 5; | Check existence. | PHP |
int[] arr = new int[95];
arr[95] = 5; | int[] arr = new int[95];
if (95 < arr.length) arr[95] = 5; | Check bounds. | Java |
my @arr = (98,41,60); | my @arr = (98,41,60); | Correct. | Perl |
let bar = 51; bar += 1; | let mut bar = 51; bar += 1; | Need mut to modify. | Rust |
values.forEach(function(z) {{ console.log(z); }}) | values.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
let foo: number | null = null; foo.toFixed(32); | let foo: number | null = null; if(foo!==null) foo.toFixed(32); | Null check. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
val z: Int = 'message' | val z: String = 'message' | Fix type. | Kotlin |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
object Person {{ def main(args: Array[String]) = println("output") }} | object Person {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
x := 72 | x := 72 | Correct. | Go |
var item int = 'value' | var item string = 'value' | Type mismatch. | Go |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
let temp: Int = 'message' | let temp: String = 'message' | Fix type. | Swift |
if [ $foo = 68 ]; then | if [ "$foo" = 68 ]; then | Quote variable. | Shell |
if (b = 97) | if (b == 97) | Use ==. | Scala |
id: result
status: test, | id: result
status: test | Remove comma. | YAML |
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