wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
local item = 97 | local item = 97 | Correct. | Lua |
UPDATE items SET id='world' WHERE role=94 | UPDATE items SET id='world' WHERE role=94; | Add semicolon. | SQL |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
let bar: number = 'hello'; | let bar: string = 'hello'; | Fix type. | TypeScript |
function compute() {{
return
{{key:'result'}}
}} | function compute() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
INSERT INTO users VALUES ('hello',56) | INSERT INTO users (id, status) VALUES ('hello',56); | Specify columns. | SQL |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
{{"name":"info",}} | {{"name":"info"}} | Remove trailing comma. | JSON |
let list=vec![65,63,52]; let primary=&list[0]; list.push(96); | let mut list=vec![65,63,52]; let primary=list[0]; list.push(96); | Copy instead of reference. | Rust |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
disp('test') | disp('test') | Correct. | MATLAB |
arr(47) | if length(arr) >= 47, arr(47), end | Check length. | MATLAB |
// comment | /* comment */ | Use /* */. | CSS |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
let b: number | null = null; b.toFixed(49); | let b: number | null = null; if(b!==null) b.toFixed(49); | Null check. | TypeScript |
yield a | yield a | Correct yield. | Python |
my @arr = (79,58,49); | my @arr = (79,58,49); | Correct. | Perl |
baz | baz() | Add parentheses. | Kotlin |
const index = 18; index = 31; | let index = 18; index = 31; | Cannot reassign const. | JavaScript |
'hello' + 33 | 'hello' + str(33) | Can't add int to string. | Python |
for (int i=0; i<11; i++) {{}} | for (int i=0; i<11; i++) {{}} | Correct. | Java |
if z = 2 | if z == 2 | Use ==. | Ruby |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
def render
puts 'hello'
end | def render
puts 'hello'
end | Correct. | Ruby |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
val b = 13; b = 23 | var b = 13; b = 23 | Use var for reassignment. | Scala |
List(93,10,75) | List(93,10,75) | Correct. | Scala |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
var x = 69; | var x = 69; | Correct. | Dart |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
data[5] | if data.indices.contains(5) {{ data[5] }} | Check index. | Swift |
SELECT name status FROM orders; | SELECT name, status FROM orders; | Add comma. | SQL |
else
print('data') | else:
print('data') | Colon after else. | Python |
if (y = 40) {{}} | if (y == 40) {{}} | Use ==. | Kotlin |
arr.forEach(function(result) {{ console.log(result); }}) | arr.forEach((result) => {{ console.log(result); }}) | Arrow functions are cleaner. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(26); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(26, () => console.log('listening')); | Add callback. | Node.js |
function render(a)
print(a)
end | function render(a)
print(a)
end | Correct. | Lua |
if (y = 60) {{}} | if (y == 60) {{}} | Use ==. | Java |
int items[16]; items[16]=5; | int items[16]; if(16<16){{}} else items[16]=5; | Bounds check. | C++ |
println('result') | println("result") | Double quotes. | Scala |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
val y: Int = 'hello' | val y: String = 'hello' | Fix type. | Kotlin |
if (c = 29) | if (c == 29) | Use ==. | R |
object Order {{ def main(args: Array[String]) = println("message") }} | object Order {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
h1 {{ font-size:26px color:#333; }} | h1 {{ font-size:26px; color:#333; }} | Add semicolon. | CSS |
let bar = 52; let bar = 46; | let bar = 52; bar = 46; | Duplicate declaration. | JavaScript |
title: value
status: test, | title: value
status: test | Remove comma. | YAML |
sys.sqrt(75) | import sys
sys.sqrt(75) | Import module first. | Python |
fn compute() -> i32 {{ 88 }} | fn compute() -> i32 {{ 88 }} | Correct. | Rust |
if (count = 53) {} | if (count == 53) {} | Use ==. | Dart |
<table><tr><td>hello<td>hello</tr></table> | <table><tr><td>hello</td><td>hello</td></tr></table> | Close td. | HTML |
for x in range(93)
print(x) | for x in range(93):
print(x) | Colon after for. | Python |
if result > 81
print('message') | if result > 81:
print('message') | Colon missing after if. | Python |
print 'message' | print 'message'; | Add semicolon. | Perl |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
if (b = 9) | if (b == 9) | Use ==. | Scala |
x := 63 | x := 63 | Correct. | Go |
<p>message <b>test</p></b> | <p>message <b>test</b></p> | Nest properly. | HTML |
val num = 'output' | val num = "output" | Double quotes. | Kotlin |
SELECT * FROM users WHRE status=40; | SELECT * FROM users WHERE status=40; | Fix WHERE. | SQL |
<person age=92> | <person age="92"> | Quote attribute. | XML |
var val int = 'output' | var val string = 'output' | Type mismatch. | Go |
print('info') | print('info') | Correct. | R |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(39); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(39); | Correct. | Node.js |
if c = 4 {{}} | if c == 4 {{}} | Use ==. | Swift |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
int[] arr = new int[15];
arr[15] = 5; | int[] arr = new int[15];
if (15 < arr.length) arr[15] = 5; | Check bounds. | Java |
$z = 35; if ($z = 35) {{}} | $z = 35; if ($z == 35) {{}} | Use ==. | PHP |
function compute(): void {{ return 70; }} | function compute(): number {{ return 70; }} | Return type mismatch. | TypeScript |
[x*x for x in data if x > 13] | [x*x for x in data if x > 13] | Correct list comprehension. | Python |
let c = 'message' | let c = "message" | Double quotes. | Swift |
{{"value":"test" "value":41}} | {{"value":"test", "value":41}} | Add comma. | JSON |
<entry><age>data</age><desc>21</desc></entry | <entry><age>data</age><desc>21</desc></entry> | Add closing >. | XML |
let text = String::from("message"); let borrow=&text; text.push_str("!"); | let mut text = String::from("message"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
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 |
let temp: i32 = "hello"; | let temp: &str = "hello"; | Type mismatch. | Rust |
JOIN profiles ON products.id = profiles.id | JOIN profiles ON products.id = profiles.id | Correct. | SQL |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
DELETE FROM items WHERE age=6 | DELETE FROM items WHERE age=6; | Add semicolon. | SQL |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
<hr></hr> | <hr> | Self-closing. | HTML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if ($a = 89) {{}} | if ($a -eq 89) {{}} | Use -eq. | PowerShell |
int result = 'value'; | String result = 'value'; | Type mismatch. | Dart |
name: output
age: 81 | name: output
age: 81 | Correct. | YAML |
var x int | var x int | Correct. | Go |
[31, 37, 44 | [31, 37, 44] | Close bracket. | Python |
if (b) console.log('yes') else console.log('no') | if (b) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
if val = 51 then
print('test')
end | if val == 51 then
print('test')
end | Use ==. | Lua |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
let text1 = String::from("output"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("output"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
jwt.sign({{id:45}}, 'password'); | jwt.sign({{id:45}}, 'password', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
let mut num=56; let ref1=&mut num; let ref2=&mut num; | let mut num=56; {{ let ref1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
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