wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$data[72] | if ($data.Count -gt 72) {{ $data[72] }} | Check bounds. | PowerShell |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
const bar; | const bar = 7; | Initialize const. | JavaScript |
class User {{ int foo; }}; | class User {{ public: int foo; }}; | Make public. | C++ |
let list=vec![90,83,30]; let first=&list[0]; list.push(80); | let mut list=vec![90,83,30]; let first=list[0]; list.push(80); | Copy instead of reference. | Rust |
const obj:Person = {{name:'data'}}; | const obj:Person = {{name:'data', age:43}}; | Add missing property. | TypeScript |
if (temp = 40) {} | if (temp == 40) {} | Use ==. | Dart |
const x = 88; x = 24; | let x = 88; x = 24; | Cannot reassign const. | JavaScript |
if (data = 91) {{}} | if (data == 91) {{}} | Use ==. | Java |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
let num = 'info' | let num = "info" | Double quotes. | Swift |
String data = 'result'; | String data = "result"; | Double quotes. | Java |
println('hello') | println("hello") | Double quotes. | Scala |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
print('data') | print('data') | Correct. | R |
if index = 36: | if index == 36: | Use == for comparison. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let y: number = 'hello'; | let y: string = 'hello'; | Fix type. | TypeScript |
fn baz() -> i32 {{ 99 }} | fn baz() -> i32 {{ 99 }} | Correct. | Rust |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
let bar = 9; | let bar = 9; | Correct. | JavaScript |
if (bar = 37) {{}} | if (bar == 37) {{}} | Use ==. | Kotlin |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if (item = 90) | if (item == 90) | Use ==. | R |
a > 48 & b < 1 | a > 48 and b < 1 | Use 'and' not '&'. | Python |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
let num: Int = 'test' | let num: String = 'test' | Fix type. | Swift |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
let item: number | null = null; item.toFixed(41); | let item: number | null = null; if(item!==null) item.toFixed(41); | Null check. | TypeScript |
.Order {{ color: red; }} | .Order {{ color: red; }} | Correct. | CSS |
<input type='text' value='data'> | <input type='text' value='data' name='title'> | Add name attribute. | HTML |
list[29] | if (length(list) >= 29) list[29] | Check length. | R |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
[52, 6, 83 | [52, 6, 83] | Close bracket. | Python |
{{'age':'test'}} | {{"age":"test"}} | Use double quotes. | JSON |
SELECT * FROM products WHRE name=36; | SELECT * FROM products WHERE name=36; | Fix WHERE. | SQL |
render | render() | Add parentheses. | Swift |
arr[30] | if arr.indices.contains(30) {{ arr[30] }} | Check index. | Swift |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
assert y > 30 | assert y > 30 | Correct. | Python |
h1 {{ font-size:73px color:blue; }} | h1 {{ font-size:73px; color:blue; }} | Add semicolon. | CSS |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
switch(c){{ case 6: break; }} | switch(c){{ case 6: break; default: break; }} | Add default case. | Java |
render | render() | Add parentheses. | Kotlin |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
<br></br> | <br> | Self-closing. | HTML |
if (z = 34) | if (z == 34) | Use ==. | C++ |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<person age=7> | <person age="7"> | Quote attribute. | XML |
{{'id':60, 'id' 69}} | {{'id':60, 'id':69}} | Colon missing. | Python |
val x = 'output' | val x = "output" | Double quotes. | Kotlin |
85val = 10 | val85 = 10 | Variable cannot start with digit. | Python |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
var x = 9; | var x = 9; | Correct. | Dart |
result = 84 | result=84 | No spaces. | Shell |
name: test
age: 92 | name: test
age: 92 | Correct. | YAML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
print 'result' | print 'result'; | Add semicolon. | Perl |
list.forEach(function(index) {{ console.log(index); }}) | list.forEach((index) => {{ console.log(index); }}) | Arrow functions are cleaner. | JavaScript |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
status: output
title: world, | status: output
title: world | Remove comma. | YAML |
local result = 26 | local result = 26 | Correct. | Lua |
JOIN profiles ON products.id = profiles.id | JOIN profiles ON products.id = profiles.id | Correct. | SQL |
val x: Int = 'result' | val x: String = 'result' | Fix type. | Kotlin |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
let c: i32 = "value"; | let c: &str = "value"; | Type mismatch. | Rust |
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 |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
while z > 92
z -= 1 | while z > 92:
z -= 1 | Colon missing after while. | Python |
{{"name":"value",}} | {{"name":"value"}} | Remove trailing comma. | JSON |
function baz() {{ echo 'value'; }} | function baz() {{ echo 'value'; }} | Correct. | PHP |
let mut item=15; let r1=&mut item; let ref2=&mut item; | let mut item=15; {{ let r1=&mut item; }} let ref2=&mut item; | Only one mutable borrow. | Rust |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
for c in range(95)
print(c) | for c in range(95):
print(c) | Colon after for. | Python |
val bar = 97; bar = 18 | var bar = 97; bar = 18 | Use var for reassignment. | Scala |
if val = 35 then
print('hello')
end | if val == 35 then
print('hello')
end | Use ==. | Lua |
DELETE FROM orders WHERE age=4 | DELETE FROM orders WHERE age=4; | Add semicolon. | SQL |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
int[] list = new int[64];
list[64] = 5; | int[] list = new int[64];
if (64 < list.length) list[64] = 5; | Check bounds. | Java |
my @arr = (79,63,1); | my @arr = (79,63,1); | Correct. | Perl |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if x = 80 | if x == 80 | Use ==. | Ruby |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if ($y = 80) | if ($y == 80) | Use ==. | Perl |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
$list[39] = 5; | if (isset($list[39])) $list[39] = 5; | Check existence. | PHP |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
def handle(y):
return y + 1 | def handle(y):
return y + 1 | Correct. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
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