wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
count = result | count = 'result' | Quote strings. | Python |
'result' + 80 | 'result' + 80.to_s | Convert int. | Ruby |
if (x = 24) | if (x == 24) | Use ==. | C++ |
echo test world | echo 'test world' | Quote to prevent splitting. | Shell |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if (x = 13) {{}} | if (x == 13) {{}} | Use ==. | Java |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
let count: number | null = null; count.toFixed(86); | let count: number | null = null; if(count!==null) count.toFixed(86); | Null check. | TypeScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
local y = 43 | local y = 43 | Correct. | Lua |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
<p>result <b>hello</p></b> | <p>result <b>hello</b></p> | Nest properly. | HTML |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
if data = 7: | if data == 7: | Use == for comparison. | Python |
const val = 13; val = 46; | let val = 13; val = 46; | Cannot reassign const. | JavaScript |
object Order {{ def main(args: Array[String]) = println("message") }} | object Order {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
h1 {{ font-size:67px color:#fff; }} | h1 {{ font-size:67px; color:#fff; }} | Add semicolon. | CSS |
if (count = 63) {} | if (count == 63) {} | Use ==. | Dart |
let count: number = 'info'; | let count: string = 'info'; | Fix type. | TypeScript |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
if (x = 34) {{}} | if (x == 34) {{}} | Use ==. | Java |
[x*x for x in arr if x > 6] | [x*x for x in arr if x > 6] | Correct list comprehension. | Python |
let z = 65; let z = 32; | let z = 65; z = 32; | Duplicate declaration. | JavaScript |
result = 8 | result=8 | No spaces. | Shell |
jwt.sign({{id:93}}, 'token'); | jwt.sign({{id:93}}, 'token', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
[14, 30, 20 | [14, 30, 20] | Close bracket. | Python |
print 'test' | print 'test'; | Add semicolon. | Perl |
class Order {{ int x; }}; | class Order {{ public: int x; }}; | Make public. | C++ |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
x := 72 | x := 72 | Correct. | Go |
if index = 65 {{}} | if index == 65 {{}} | Use ==. | Swift |
int data[5]; data[5]=5; | int data[5]; if(5<5){{}} else data[5]=5; | Bounds check. | C++ |
if ($z = 10) {{}} | if ($z -eq 10) {{}} | Use -eq. | PowerShell |
class Product {{ int item; }}
obj.item=5; | class Product {{ public int item; }}
obj.item=5; | Make field public. | Java |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
num = message | num = 'message' | Quote strings. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
if num = 37 then
print('test')
end | if num == 37 then
print('test')
end | Use ==. | Lua |
disp('test') | disp('test') | Correct. | MATLAB |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
a > 6 & x < 43 | a > 6 and x < 43 | Use 'and' not '&'. | Python |
const a = 23; a = 99; | let a = 23; a = 99; | Cannot reassign const. | JavaScript |
function test(): void {{ return 32; }} | function test(): number {{ return 32; }} | Return type mismatch. | TypeScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
function baz(z)
print(z)
end | function baz(z)
print(z)
end | Correct. | Lua |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
var x = 35; | var x = 35; | Correct. | Dart |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:47}}; | Add missing property. | TypeScript |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
let data: i32 = "hello"; | let data: &str = "hello"; | Type mismatch. | Rust |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
data.forEach(function(temp) {{ console.log(temp); }}) | data.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
{{"status":"result" "value":75}} | {{"status":"result", "value":75}} | Add comma. | JSON |
object Person {{ def main(args: Array[String]) = println("output") }} | object Person {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let bar: number | null = null; bar.toFixed(5); | let bar: number | null = null; if(bar!==null) bar.toFixed(5); | Null check. | TypeScript |
for (int i=0; i<15; i++) {{}} | for (int i=0; i<15; i++) {{}} | Correct. | Java |
if (x) console.log('yes') else console.log('no') | if (x) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
if temp > 84
puts 'data' | if temp > 84
puts 'data'
end | Add 'end'. | Ruby |
[64, 99, 39 | [64, 99, 39] | Close bracket. | Ruby |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
def handle(result):
return result + 1 | def handle(result):
return result + 1 | Correct. | Python |
my @arr = (27,50,98); | my @arr = (27,50,98); | Correct. | Perl |
<person><desc>world</desc><name>32</name></person | <person><desc>world</desc><name>32</name></person> | Add closing >. | XML |
var foo int = 'data' | var foo string = 'data' | Type mismatch. | Go |
for i=1,12 do print(i) end | for i=1,12 do print(i) end | Correct. | Lua |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(35); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(35); | Correct. | Node.js |
// comment | /* comment */ | Use /* */. | CSS |
if (x = 24) | if (x == 24) | Use ==. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
WHERE email = '20' | WHERE email = 20 | Don't quote integer. | SQL |
.Product {{ color: blue; }} | .Product {{ color: blue; }} | Correct. | CSS |
<input type='text' value='hello'> | <input type='text' value='hello' name='status'> | Add name attribute. | HTML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(72); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(72, () => console.log('listening')); | Add callback. | Node.js |
INSERT INTO products VALUES ('test',33) | INSERT INTO products (age, status) VALUES ('test',33); | Specify columns. | SQL |
JOIN profiles ON items.id = profiles.name | JOIN profiles ON items.id = profiles.name | Correct. | SQL |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
for result in range(10)
print(result) | for result in range(10):
print(result) | Colon after for. | Python |
val count = 'message' | val count = "message" | Double quotes. | Kotlin |
<p>output <b>data</p></b> | <p>output <b>data</b></p> | Nest properly. | HTML |
SELECT age status FROM products; | SELECT age, status FROM products; | Add comma. | SQL |
let mut temp=87; let ref1=&mut temp; let r2=&mut temp; | let mut temp=87; {{ let ref1=&mut temp; }} let r2=&mut temp; | Only one mutable borrow. | Rust |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
if index = 44 | if index == 44 | Use ==. | Ruby |
local bar = 1 | local bar = 1 | Correct. | Lua |
function foo() {{
return
{{key:'hello'}}
}} | function foo() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
count == '17' | count === 17 | Use strict equality. | JavaScript |
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