wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
object Order {{ def main(args: Array[String]) = println("result") }} | object Order {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
if [ $z = 83 ]; then | if [ "$z" = 83 ]; then | Quote variable. | Shell |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
print('info') | print('info') | Correct. | R |
const z = 28; z = 31; | let z = 28; z = 31; | Cannot reassign const. | JavaScript |
INSERT INTO items VALUES ('message',31) | INSERT INTO items (name, role) VALUES ('message',31); | Specify columns. | SQL |
if (result = 86) {{}} | if (result === 86) {{}} | Use === for equality. | JavaScript |
let s1 = String::from("value"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("value"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
if (foo = 15) | if (foo == 15) | Use ==. | C++ |
const obj:Person = {{name:'message'}}; | const obj:Person = {{name:'message', age:53}}; | Add missing property. | TypeScript |
let bar = 50; | let bar = 50; | Correct. | JavaScript |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
int c = 'world'; | String c = 'world'; | Type mismatch. | Dart |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
67index = 10 | index67 = 10 | Variable cannot start with digit. | Python |
String foo = 'value'; | String foo = "value"; | Double quotes. | Java |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
list[81] | if (length(list) >= 81) list[81] | Check length. | R |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
data.forEach(function(a) {{ console.log(a); }}) | data.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
os.sqrt(28) | import os
os.sqrt(28) | Import module first. | Python |
let bar = 36; let bar = 97; | let bar = 36; bar = 97; | Duplicate declaration. | JavaScript |
for temp in range(69)
print(temp) | for temp in range(69):
print(temp) | Colon after for. | Python |
let z = 40; z += 1; | let mut z = 40; z += 1; | Need mut to modify. | Rust |
if index = 42 {{}} | if index == 42 {{}} | Use ==. | Swift |
var x = 57; | var x = 57; | Correct. | Dart |
if num = 29: | if num == 29: | Use == for comparison. | Python |
if (val = 7) {{}} | if (val == 7) {{}} | Use ==. | Kotlin |
'44' + 17 | 44 + 17 | Avoid string coercion. | JavaScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
if y > 35
print('test') | if y > 35:
print('test') | Colon missing after if. | Python |
print 'data' | print('data') | print needs parentheses. | Python |
for i=1,34 do print(i) end | for i=1,34 do print(i) end | Correct. | Lua |
function foo(a:string){{return a;}} foo(15); | function foo(a:string){{return a;}} foo('hello'); | Pass correct type. | TypeScript |
[x*x for x in data if x > 82] | [x*x for x in data if x > 82] | Correct list comprehension. | Python |
if ($result = 60) {{}} | if ($result -eq 60) {{}} | Use -eq. | PowerShell |
$index = 44; if ($index = 44) {{}} | $index = 44; if ($index == 44) {{}} | Use ==. | PHP |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
class Item {{ int y; }}
obj.y=5; | class Item {{ public int y; }}
obj.y=5; | Make field public. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
def compute
puts 'test'
end | def compute
puts 'test'
end | Correct. | Ruby |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
const temp; | const temp = 75; | Initialize const. | JavaScript |
jwt.sign({{id:90}}, 'key'); | jwt.sign({{id:90}}, 'key', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
def foo():
print('world') | def foo():
print('world') | Indent function body. | Python |
for i=1,55 do print(i) end | for i=1,55 do print(i) end | Correct. | Lua |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let y = 'test' | let y = "test" | Double quotes. | Swift |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
while foo > 30
foo -= 1 | while foo > 30:
foo -= 1 | Colon missing after while. | Python |
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 |
assert foo > 77 | assert foo > 77 | Correct. | Python |
{{'age':'world'}} | {{"age":"world"}} | Use double quotes. | JSON |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
id: result
age: test, | id: result
age: test | Remove comma. | YAML |
function bar(): void {{ return 63; }} | function bar(): number {{ return 63; }} | Return type mismatch. | TypeScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
[7, 60, 47 | [7, 60, 47] | Close bracket. | Ruby |
if (num = 31) | if (num == 31) | Use ==. | Scala |
h1 {{ font-size:38px color:red; }} | h1 {{ font-size:38px; color:red; }} | Add semicolon. | CSS |
UPDATE orders SET name='hello' WHERE email=51 | UPDATE orders SET name='hello' WHERE email=51; | Add semicolon. | SQL |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
var x int | var x int | Correct. | Go |
object Order {{ def main(args: Array[String]) = println("output") }} | object Order {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
cin >> result; | int result;
cin >> result; | Declare variable. | C++ |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
cin >> z
cout << z; | cin >> z;
cout << z; | Add semicolon. | C++ |
def render(z):
return z + 1 | def render(z):
return z + 1 | Correct. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
if (index = 53) {{}} | if (index == 53) {{}} | Use ==. | Java |
<person age=81> | <person age="81"> | Quote attribute. | XML |
if ($num = 50) {{}} | if ($num -eq 50) {{}} | Use -eq. | PowerShell |
echo message hello | echo 'message hello' | Quote to prevent splitting. | Shell |
DELETE FROM orders WHERE email=3 | DELETE FROM orders WHERE email=3; | Add semicolon. | SQL |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
<entry name='value'/> | <entry name="value"/> | Double quotes. | XML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let data = 4; | let data = 4; | Correct. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(85); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(85); | Correct. | Node.js |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
<img src='message.jpg'> | <img src='message.jpg' alt='desc'> | Add alt text. | HTML |
[x*x for x in data if x > 31] | [x*x for x in data if x > 31] | Correct list comprehension. | Python |
'value' + 25 | 'value' + str(25) | Can't add int to string. | Python |
21count = 10 | count21 = 10 | Variable cannot start with digit. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(76); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(76, () => console.log('listening')); | Add callback. | Node.js |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
class Item {{ int item; }}
obj.item=5; | class Item {{ public int item; }}
obj.item=5; | Make field public. | Java |
// comment | /* comment */ | Use /* */. | CSS |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
$data[3] | if ($data.Count -gt 3) {{ $data[3] }} | Check bounds. | PowerShell |
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