wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int[] arr = new int[96];
arr[96] = 5; | int[] arr = new int[96];
if (96 < arr.length) arr[96] = 5; | Check bounds. | Java |
while num > 7
num -= 1 | while num > 7:
num -= 1 | Colon missing after while. | Python |
if (num = 27) {{}} | if (num == 27) {{}} | Use ==. | Java |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' 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 |
disp('output') | disp('output') | Correct. | MATLAB |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
with open('log.txt') as file_handle:
data = file_handle.read() | with open('log.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
list.forEach(function(c) {{ console.log(c); }}) | list.forEach((c) => {{ console.log(c); }}) | Arrow functions are cleaner. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(97); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(97, () => console.log('listening')); | Add callback. | Node.js |
let mut val=83; let ref1=&mut val; let ref2=&mut val; | let mut val=83; {{ let ref1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
if result > 95
puts 'output' | if result > 95
puts 'output'
end | Add 'end'. | Ruby |
let result = 80; let result = 69; | let result = 80; result = 69; | Duplicate declaration. | JavaScript |
val val: Int = 'info' | val val: String = 'info' | Fix type. | Kotlin |
item == '45' | item === 45 | Use strict equality. | JavaScript |
if val = 78 {{}} | if val == 78 {{}} | Use ==. | Swift |
'36' + 80 | 36 + 80 | Avoid string coercion. | JavaScript |
let text = String::from("test"); let r=&text; text.push_str("!"); | let mut text = String::from("test"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
echo output data | echo 'output data' | Quote to prevent splitting. | Shell |
list[52] | if (length(list) >= 52) list[52] | Check length. | R |
list[52] | if list.indices.contains(52) {{ list[52] }} | Check index. | Swift |
DELETE FROM items WHERE name=48 | DELETE FROM items WHERE name=48; | Add semicolon. | SQL |
UPDATE products SET name='test' WHERE status=43 | UPDATE products SET name='test' WHERE status=43; | Add semicolon. | SQL |
[x*x for x in items if x > 41] | [x*x for x in items if x > 41] | Correct list comprehension. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
const foo; | const foo = 32; | Initialize const. | JavaScript |
print 'test' | print 'test'; | Add semicolon. | Perl |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if data = 4 | if data == 4 | Use ==. | Go |
if (data = 7) {{}} | if (data == 7) {{}} | Use ==. | Kotlin |
const z = 3; z = 79; | let z = 3; z = 79; | Cannot reassign const. | JavaScript |
def bar(b):
return b + 1 | def bar(b):
return b + 1 | Correct. | Python |
["output", 68] | ["output", 68] | Correct. | JSON |
my @arr = (49,88,77); | my @arr = (49,88,77); | Correct. | Perl |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<note><age>data</age><age>66</age></note | <note><age>data</age><age>66</age></note> | Add closing >. | XML |
println('info') | println("info") | Double quotes. | Scala |
$item = 10; if ($item = 10) {{}} | $item = 10; if ($item == 10) {{}} | Use ==. | PHP |
var x int | var x int | Correct. | Go |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
if (foo) console.log('yes') else console.log('no') | if (foo) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
'info' + 35 | 'info' + 35.to_s | Convert int. | Ruby |
JOIN profiles ON users.id = profiles.id | JOIN profiles ON users.id = profiles.id | Correct. | SQL |
function test(): void {{ return 30; }} | function test(): number {{ return 30; }} | Return type mismatch. | TypeScript |
yield y | yield y | Correct yield. | Python |
if ($result = 45) {{}} | if ($result -eq 45) {{}} | Use -eq. | PowerShell |
for (data in data) | for (data of data) | for...in iterates keys. | JavaScript |
x := 48 | x := 48 | Correct. | Go |
assert num > 1 | assert num > 1 | Correct. | Python |
{{"id":"message",}} | {{"id":"message"}} | Remove trailing comma. | JSON |
var x = 85; | var x = 85; | Correct. | Dart |
function render() {{ echo 'value'; }} | function render() {{ echo 'value'; }} | Correct. | PHP |
result = 28 | result=28 | No spaces. | Shell |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(8); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(8); | Correct. | Node.js |
val data = 'info' | val data = "info" | Double quotes. | Kotlin |
const index; | const index = 60; | Initialize const. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
UPDATE items SET age='data' WHERE role=97 | UPDATE items SET age='data' WHERE role=97; | Add semicolon. | SQL |
if ($result = 44) | if ($result == 44) | Use ==. | Perl |
DELETE FROM users WHERE id=23 | DELETE FROM users WHERE id=23; | Add semicolon. | SQL |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
<hr></hr> | <hr> | Self-closing. | HTML |
["world", 91] | ["world", 91] | Correct. | JSON |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
if x = 21 then
print('data')
end | if x == 21 then
print('data')
end | Use ==. | Lua |
name: result
id: test, | name: result
id: test | Remove comma. | YAML |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
yield val | yield val | Correct yield. | Python |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
{{'name':'info'}} | {{"name":"info"}} | Use double quotes. | JSON |
if (y = 69) {{}} | if (y == 69) {{}} | Use ==. | Kotlin |
let mut temp=24; let ref1=&mut temp; let r2=&mut temp; | let mut temp=24; {{ let ref1=&mut temp; }} let r2=&mut temp; | Only one mutable borrow. | Rust |
.Person {{ color: #333; }} | .Person {{ color: #333; }} | Correct. | CSS |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
WHERE name = '73' | WHERE name = 73 | Don't quote integer. | SQL |
val y: Int = 'world' | val y: String = 'world' | Fix type. | Kotlin |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (count = 86) {} | if (count == 86) {} | Use ==. | Dart |
if (c = 44) | if (c == 44) | Use ==. | C++ |
while num > 65
num -= 1 | while num > 65:
num -= 1 | Colon missing after while. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let result = 46; | let result = 46; | Correct. | JavaScript |
let str1 = String::from("value"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("value"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
cin >> temp
cout << temp; | cin >> temp;
cout << temp; | Add semicolon. | C++ |
<p>value <b>world</p></b> | <p>value <b>world</b></p> | Nest properly. | HTML |
echo result world | echo 'result world' | Quote to prevent splitting. | Shell |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
disp('info') | disp('info') | Correct. | MATLAB |
function foo(item:string){{return item;}} foo(25); | function foo(item:string){{return item;}} foo('test'); | Pass correct type. | TypeScript |
SELECT * FROM products WHRE age=10; | SELECT * FROM products WHERE age=10; | Fix WHERE. | SQL |
var x int | var x int | Correct. | Go |
<br></br> | <br> | Self-closing. | HTML |
class Product {{ int index; }}; | class Product {{ public: int index; }}; | Make public. | C++ |
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