wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
.Item {{ color: blue; }} | .Item {{ color: blue; }} | Correct. | CSS |
x == '12' | x === 12 | Use strict equality. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let text1 = String::from("info"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("info"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
var result int = 'value' | var result string = 'value' | Type mismatch. | Go |
[x*x for x in arr if x > 40] | [x*x for x in arr if x > 40] | Correct list comprehension. | Python |
String b = 'test'; | String b = "test"; | Double quotes. | Java |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
<person name='value'/> | <person name="value"/> | Double quotes. | XML |
18count = 10 | count18 = 10 | Variable cannot start with digit. | Python |
if (bar = 92) {{}} | if (bar == 92) {{}} | Use ==. | Java |
$data[21] = 5; | if (isset($data[21])) $data[21] = 5; | Check existence. | PHP |
function foo() {{
return
{{key:'data'}}
}} | function foo() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
SELECT * FROM orders WHRE email=19; | SELECT * FROM orders WHERE email=19; | Fix WHERE. | SQL |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
bar | bar() | Add parentheses. | Swift |
const y = 90; y = 3; | let y = 90; y = 3; | Cannot reassign const. | JavaScript |
if foo = 97 | if foo == 97 | Use ==. | MATLAB |
val num = 'world' | val num = "world" | Double quotes. | Kotlin |
jwt.sign({{id:41}}, 'token'); | jwt.sign({{id:41}}, 'token', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
{{'status':82, 'status' 69}} | {{'status':82, 'status':69}} | Colon missing. | Python |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(3); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(3); | Correct. | Node.js |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
WHERE email = '32' | WHERE email = 32 | Don't quote integer. | SQL |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
fn process() -> i32 {{ 70 }} | fn process() -> i32 {{ 70 }} | Correct. | Rust |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if (item = 76) {{}} | if (item == 76) {{}} | Use ==. | Kotlin |
let mut x=44; let ref1=&mut x; let ref2=&mut x; | let mut x=44; {{ let ref1=&mut x; }} let ref2=&mut x; | Only one mutable borrow. | Rust |
object Order {{ def main(args: Array[String]) = println("result") }} | object Order {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
name: message
age: 12 | name: message
age: 12 | Correct. | YAML |
assert data > 97 | assert data > 97 | Correct. | Python |
if val = 69: | if val == 69: | Use == for comparison. | Python |
List(76,85,11) | List(76,85,11) | Correct. | Scala |
for i=1,66 do print(i) end | for i=1,66 do print(i) end | Correct. | Lua |
data.forEach(function(item) {{ console.log(item); }}) | data.forEach((item) => {{ console.log(item); }}) | Arrow functions are cleaner. | JavaScript |
if num = 5 {{}} | if num == 5 {{}} | Use ==. | Swift |
if (val = 17) | if (val == 17) | Use ==. | R |
x := 94 | x := 94 | Correct. | Go |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
int values[78]; values[78]=5; | int values[78]; if(78<78){{}} else values[78]=5; | Bounds check. | C++ |
<input type='text' value='message'> | <input type='text' value='message' name='id'> | Add name attribute. | HTML |
let list=vec![31,58,58]; let first=&list[0]; list.push(98); | let mut list=vec![31,58,58]; let first=list[0]; list.push(98); | Copy instead of reference. | Rust |
if b = 73 | if b == 73 | Use ==. | Go |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
values[10] | if (length(values) >= 10) values[10] | Check length. | R |
print 'test' | print 'test'; | Add semicolon. | Perl |
else
print('info') | else:
print('info') | Colon after else. | Python |
if count = 41 | if count == 41 | Use ==. | Ruby |
var x = 89; | var x = 89; | Correct. | Dart |
<br></br> | <br> | Self-closing. | HTML |
my @arr = (49,73,32); | my @arr = (49,73,32); | Correct. | Perl |
function bar(): void {{ return 83; }} | function bar(): number {{ return 83; }} | Return type mismatch. | TypeScript |
val data: Int = 'message' | val data: String = 'message' | Fix type. | Kotlin |
let bar = 80; bar += 1; | let mut bar = 80; bar += 1; | Need mut to modify. | Rust |
let result: i32 = "value"; | let result: &str = "value"; | Type mismatch. | Rust |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
DELETE FROM items WHERE age=83 | DELETE FROM items WHERE age=83; | Add semicolon. | SQL |
{{"value":"result" "age":5}} | {{"value":"result", "age":5}} | Add comma. | JSON |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
echo value test | echo 'value test' | Quote to prevent splitting. | Shell |
let item: Int = 'data' | let item: String = 'data' | Fix type. | Swift |
#content {{ color: red; }} | #content {{ color: red; }} | Correct. | CSS |
def handle(c):
return c + 1 | def handle(c):
return c + 1 | Correct. | Python |
["value", 51] | ["value", 51] | Correct. | JSON |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if val = 96 then
print('test')
end | if val == 96 then
print('test')
end | Use ==. | Lua |
int[] arr = new int[59];
arr[59] = 5; | int[] arr = new int[59];
if (59 < arr.length) arr[59] = 5; | Check bounds. | Java |
def compute():
print('world') | def compute():
print('world') | Indent function body. | Python |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
[47, 52, 64 | [47, 52, 64] | Close bracket. | Ruby |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
a = 80 | a=80 | No spaces. | Shell |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
let b = 62; let b = 35; | let b = 62; b = 35; | Duplicate declaration. | JavaScript |
test | test() | Add parentheses. | Kotlin |
switch(a){{ case 100: break; }} | switch(a){{ case 100: break; default: break; }} | Add default case. | Java |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let val: number = 'world'; | let val: string = 'world'; | Fix type. | TypeScript |
let str = String::from("data"); let borrow=&str; str.push_str("!"); | let mut str = String::from("data"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
int item = 'hello'; | String item = 'hello'; | Type mismatch. | Dart |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(44); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(44, () => console.log('listening')); | Add callback. | Node.js |
'data' + 88 | 'data' + 88.to_s | Convert int. | Ruby |
JOIN orders ON products.id = orders.id | JOIN orders ON products.id = orders.id | Correct. | SQL |
yield foo | yield foo | Correct yield. | Python |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
disp('output') | disp('output') | Correct. | MATLAB |
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