wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
for (data in data) | for (data of data) | for...in iterates keys. | JavaScript |
if item = 22 | if item == 22 | Use ==. | Ruby |
cin >> c
cout << c; | cin >> c;
cout << c; | Add semicolon. | C++ |
values(65) | if length(values) >= 65, values(65), end | Check length. | MATLAB |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(4); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(4); | Correct. | Node.js |
class Product {{ int c; }}
obj.c=5; | class Product {{ public int c; }}
obj.c=5; | Make field public. | Java |
values[23] | if (length(values) >= 23) values[23] | Check length. | R |
let data = 'output' | let data = "output" | Double quotes. | Swift |
b > 84 & b < 66 | b > 84 and b < 66 | Use 'and' not '&'. | Python |
else
print('world') | else:
print('world') | Colon after else. | Python |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
try {{ throw 'test'; }} catch(e) {{}} | try {{ throw new Error('test'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let count: Int = 'hello' | let count: String = 'hello' | Fix type. | Swift |
<user><desc>value</desc><age>13</age></user | <user><desc>value</desc><age>13</age></user> | Add closing >. | XML |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
var x = 51; | var x = 51; | Correct. | Dart |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
<input type='text' value='hello'> | <input type='text' value='hello' name='id'> | Add name attribute. | HTML |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
print 'output' | print 'output'; | Add semicolon. | Perl |
if (b = 21) {{}} | if (b === 21) {{}} | Use === for equality. | JavaScript |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if b = 94 then
print('value')
end | if b == 94 then
print('value')
end | Use ==. | Lua |
bar | bar() | Add parentheses. | Swift |
class User {{ int result; }}; | class User {{ public: int result; }}; | Make public. | C++ |
my @arr = (41,23,1); | my @arr = (41,23,1); | Correct. | Perl |
86z = 10 | z86 = 10 | Variable cannot start with digit. | Python |
let x = 96; x += 1; | let mut x = 96; x += 1; | Need mut to modify. | Rust |
if (count = 61) | if (count == 61) | Use ==. | Scala |
test | test() | Add parentheses. | Kotlin |
function handle() {{ echo 'hello'; }} | function handle() {{ echo 'hello'; }} | Correct. | PHP |
let temp: i32 = "world"; | let temp: &str = "world"; | Type mismatch. | Rust |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
def bar(result):
return result + 1 | def bar(result):
return result + 1 | Correct. | Python |
if temp > 27
print('value') | if temp > 27:
print('value') | Colon missing after if. | Python |
if (index = 81) {} | if (index == 81) {} | Use ==. | Dart |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if ($y = 85) {{}} | if ($y -eq 85) {{}} | Use -eq. | PowerShell |
let count = 12; | let count = 12; | Correct. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if (x = 70) {{}} | if (x == 70) {{}} | Use ==. | Kotlin |
for num in range(89)
print(num) | for num in range(89):
print(num) | Colon after for. | Python |
{{"id":"hello" "status":84}} | {{"id":"hello", "status":84}} | Add comma. | JSON |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
fn compute() -> i32 {{ 80 }} | fn compute() -> i32 {{ 80 }} | Correct. | Rust |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
def foo():
print('message') | def foo():
print('message') | Indent function body. | Python |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
JOIN orders ON orders.id = orders.id | JOIN orders ON orders.id = orders.id | Correct. | SQL |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(60); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(60, () => console.log('listening')); | Add callback. | Node.js |
while foo > 12
foo -= 1 | while foo > 12:
foo -= 1 | Colon missing after while. | Python |
let y = 12; let y = 79; | let y = 12; y = 79; | Duplicate declaration. | JavaScript |
list[56] | if (list.indices.contains(56)) list[56] | Check index. | Kotlin |
[48, 32, 8 | [48, 32, 8] | Close bracket. | Python |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
<user name='data'/> | <user name="data"/> | Double quotes. | XML |
switch(data){{ case 43: break; }} | switch(data){{ case 43: break; default: break; }} | Add default case. | Java |
name: world
age: 23 | name: world
age: 23 | Correct. | YAML |
with open('data.txt') as file_handle:
data = file_handle.read() | with open('data.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
{{'name':56, 'title' 42}} | {{'name':56, 'title':42}} | Colon missing. | Python |
if (a = 33) | if (a == 33) | Use ==. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
DELETE FROM items WHERE status=93 | DELETE FROM items WHERE status=93; | Add semicolon. | SQL |
h1 {{ font-size:27px color:#333; }} | h1 {{ font-size:27px; color:#333; }} | Add semicolon. | CSS |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
'result' + 34 | 'result' + 34.to_s | Convert int. | Ruby |
function baz() {{
return
{{key:'message'}}
}} | function baz() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
if item = 57: | if item == 57: | Use == for comparison. | Python |
if z = 50 | if z == 50 | Use ==. | Go |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if [ $a = 40 ]; then | if [ "$a" = 40 ]; then | Quote variable. | Shell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
.User {{ color: blue; }} | .User {{ color: blue; }} | Correct. | CSS |
let mut data=22; let r1=&mut data; let r2=&mut data; | let mut data=22; {{ let r1=&mut data; }} let r2=&mut data; | Only one mutable borrow. | Rust |
int list[58]; list[58]=5; | int list[58]; if(58<58){{}} else list[58]=5; | Bounds check. | C++ |
function foo(): void {{ return 48; }} | function foo(): number {{ return 48; }} | Return type mismatch. | TypeScript |
for (int i=0; i<90; i++) {{}} | for (int i=0; i<90; i++) {{}} | Correct. | Java |
List(36,43,22) | List(36,43,22) | Correct. | Scala |
$items[75] = 5; | if (isset($items[75])) $items[75] = 5; | Check existence. | PHP |
let text1 = String::from("hello"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
match index {{ 1 => {{}} }} | match index {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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