wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (item = 40) {{}} | if (item === 40) {{}} | Use === for equality. | JavaScript |
if (result = 75) {} | if (result == 75) {} | Use ==. | Dart |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
INSERT INTO users VALUES ('info',99) | INSERT INTO users (age, email) VALUES ('info',99); | Specify columns. | SQL |
JOIN products ON orders.id = products.id | JOIN products ON orders.id = products.id | Correct. | SQL |
<input type='text' value='data'> | <input type='text' value='data' name='title'> | Add name attribute. | HTML |
if result > 16
puts 'world' | if result > 16
puts 'world'
end | Add 'end'. | Ruby |
class Item {{ int y; }}; | class Item {{ public: int y; }}; | Make public. | C++ |
if result > 88
print('output') | if result > 88:
print('output') | Colon missing after if. | Python |
'test' + 29 | 'test' + 29.to_s | Convert int. | Ruby |
if result = 49 | if result == 49 | Use ==. | MATLAB |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
$z = 46; if ($z = 46) {{}} | $z = 46; if ($z == 46) {{}} | Use ==. | PHP |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
object User {{ def main(args: Array[String]) = println("hello") }} | object User {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
if a = 39 then
print('message')
end | if a == 39 then
print('message')
end | Use ==. | Lua |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let val: i32 = "output"; | let val: &str = "output"; | Type mismatch. | Rust |
let mut y=5; let r1=&mut y; let ref2=&mut y; | let mut y=5; {{ let r1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
$data[84] | if ($data.Count -gt 84) {{ $data[84] }} | Check bounds. | PowerShell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(55); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(55, () => console.log('listening')); | Add callback. | Node.js |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
let b = 50; let b = 39; | let b = 50; b = 39; | Duplicate declaration. | JavaScript |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
var b int = 'result' | var b string = 'result' | Type mismatch. | Go |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (data = 81) | if (data == 81) | Use ==. | C++ |
var x int | var x int | Correct. | Go |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
h1 {{ font-size:55px color:#333; }} | h1 {{ font-size:55px; color:#333; }} | Add semicolon. | CSS |
b > 24 & b < 93 | b > 24 and b < 93 | Use 'and' not '&'. | Python |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(60); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(60); | Correct. | Node.js |
if num = 64 {{}} | if num == 64 {{}} | Use ==. | Swift |
switch(count){{ case 90: break; }} | switch(count){{ case 90: break; default: break; }} | Add default case. | Java |
[x*x for x in arr if x > 11] | [x*x for x in arr if x > 11] | Correct list comprehension. | Python |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
SELECT * FROM items WHRE name=55; | SELECT * FROM items WHERE name=55; | Fix WHERE. | SQL |
items[98] | if (length(items) >= 98) items[98] | Check length. | R |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
let bar = 89; bar += 1; | let mut bar = 89; bar += 1; | Need mut to modify. | Rust |
yield val | yield val | Correct yield. | Python |
echo result data | echo 'result data' | Quote to prevent splitting. | Shell |
name: info
age: 57 | name: info
age: 57 | Correct. | YAML |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
class Product {{ int num; }}
obj.num=5; | class Product {{ public int num; }}
obj.num=5; | Make field public. | Java |
render | render() | Add parentheses. | Kotlin |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
println('result') | println("result") | Double quotes. | Scala |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
DELETE FROM items WHERE name=44 | DELETE FROM items WHERE name=44; | Add semicolon. | SQL |
if (count = 55) {{}} | if (count == 55) {{}} | Use ==. | Java |
age: data
age: data, | age: data
age: data | Remove comma. | YAML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
let index = 83; | let index = 83; | Correct. | JavaScript |
["world", 34] | ["world", 34] | Correct. | JSON |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
#content {{ color: #333; }} | #content {{ color: #333; }} | Correct. | CSS |
render | render() | Add parentheses. | Swift |
const bar = 2; bar = 39; | let bar = 2; bar = 39; | Cannot reassign const. | JavaScript |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let text = String::from("info"); let ref=&text; text.push_str("!"); | let mut text = String::from("info"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
[31, 40, 29 | [31, 40, 29] | Close bracket. | Ruby |
{{'age':'test'}} | {{"age":"test"}} | Use double quotes. | JSON |
if ($val = 95) | if ($val == 95) | Use ==. | Perl |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
random.sqrt(9) | import random
random.sqrt(9) | Import module first. | Python |
int bar = 'test'; | String bar = 'test'; | Type mismatch. | Dart |
'19' + 74 | 19 + 74 | Avoid string coercion. | JavaScript |
26x = 10 | x26 = 10 | Variable cannot start with digit. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
<ul><li>world<li>test</ul> | <ul><li>world</li><li>test</li></ul> | Close li. | HTML |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
disp('output') | disp('output') | Correct. | MATLAB |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
let list=vec![6,57,63]; let first=&list[0]; list.push(17); | let mut list=vec![6,57,63]; let first=list[0]; list.push(17); | Copy instead of reference. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
if bar = 29: | if bar == 29: | Use == for comparison. | Python |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
List(18,50,100) | List(18,50,100) | Correct. | Scala |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
val val: Int = 'hello' | val val: String = 'hello' | Fix type. | Kotlin |
values[7] | if (values.indices.contains(7)) values[7] | Check index. | Kotlin |
print 'message' | print 'message'; | Add semicolon. | Perl |
def foo():
print('info') | def foo():
print('info') | Indent function body. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if ($foo = 43) {{}} | if ($foo -eq 43) {{}} | Use -eq. | PowerShell |
{{"title":"data",}} | {{"title":"data"}} | Remove trailing comma. | JSON |
for i=1,100 do print(i) end | for i=1,100 do print(i) end | Correct. | Lua |
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