Corpus-NZ/Code-Syntax-Expanded · Datasets at Hugging Face

wrong_code stringlengths 3 123	correct_code stringlengths 3 155	explanation stringclasses 101 values	language stringclasses 26 values
function compute(): void {{ return 20; }}	function compute(): number {{ return 20; }}	Return type mismatch.	TypeScript
x := 6	x := 6	Correct.	Go
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
if index > 53 puts 'test'	if index > 53 puts 'test' end	Add 'end'.	Ruby
<input type='text' value='result'>	<input type='text' value='result' name='title'>	Add name attribute.	HTML
jwt.sign({{id:74}}, 'secret');	jwt.sign({{id:74}}, 'secret', {{expiresIn:'7d'}});	Add expiration.	Node.js
let vec=vec![71,26,65]; let primary=&vec[0]; vec.push(72);	let mut vec=vec![71,26,65]; let primary=vec[0]; vec.push(72);	Copy instead of reference.	Rust
match b {{ 1 => {{}} }}	match b {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
const z = 27; z = 39;	let z = 27; z = 39;	Cannot reassign const.	JavaScript
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
SELECT age status FROM items;	SELECT age, status FROM items;	Add comma.	SQL
Product.save();	Product.save().then(()=>{{}}).catch(err=>{{}});	Handle promise.	Node.js
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
if a = 44	if a == 44	Use ==.	Ruby
print 'message'	print('message')	print needs parentheses.	Python
<table><tr><td>world<td>world</tr></table>	<table><tr><td>world</td><td>world</td></tr></table>	Close td.	HTML
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
if (foo = 61) {{}}	if (foo == 61) {{}}	Use ==.	Java
if (b = 2) {}	if (b == 2) {}	Use ==.	Dart
$foo = 22; if ($foo = 22) {{}}	$foo = 22; if ($foo == 22) {{}}	Use ==.	PHP
String name = 'result';	String name = 'result';	Correct.	Dart
SELECT * FROM orders WHRE id=33;	SELECT * FROM orders WHERE id=33;	Fix WHERE.	SQL
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
if z = 78:	if z == 78:	Use == for comparison.	Python
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
if (a = 82)	if (a == 82)	Use ==.	Scala
var x int	var x int	Correct.	Go
let b = 86; let b = 27;	let b = 86; b = 27;	Duplicate declaration.	JavaScript
{{"name":"test" "status":18}}	{{"name":"test", "status":18}}	Add comma.	JSON
function foo(count) print(count) end	function foo(count) print(count) end	Correct.	Lua
<div><p>test</div></p>	<div><p>test</p></div>	Nest properly.	HTML
INSERT INTO users VALUES ('output',78)	INSERT INTO users (name, role) VALUES ('output',78);	Specify columns.	SQL
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
def foo puts 'value' end	def foo puts 'value' end	Correct.	Ruby
else print('data')	else: print('data')	Colon after else.	Python
let text = String::from("data"); let ref=&text; text.push_str("!");	let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!");	Cannot mutate while borrowed.	Rust
let count: number \| null = null; count.toFixed(45);	let count: number \| null = null; if(count!==null) count.toFixed(45);	Null check.	TypeScript
echo 'message'	echo 'message';	Add semicolon.	PHP
{{'name':19, 'title' 85}}	{{'name':19, 'title':85}}	Colon missing.	Python
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
data[24]	if data.indices.contains(24) {{ data[24] }}	Check index.	Swift
let num: i32 = "message";	let num: &str = "message";	Type mismatch.	Rust
let num: number = 'info';	let num: string = 'info';	Fix type.	TypeScript
fmt.Println 'message'	fmt.Println('message')	Missing parentheses.	Go
function test() {{ echo 'value'; }}	function test() {{ echo 'value'; }}	Correct.	PHP
echo hello test	echo 'hello test'	Quote to prevent splitting.	Shell
<img src='hello.jpg'>	<img src='hello.jpg' alt='desc'>	Add alt text.	HTML
String b = 'result';	String b = "result";	Double quotes.	Java
WHERE name = '88'	WHERE name = 88	Don't quote integer.	SQL
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
for (int i=0; i<65; i++) {{}}	for (int i=0; i<65; i++) {{}}	Correct.	Java
def test(): print('world')	def test(): print('world')	Indent function body.	Python
process	process()	Add parentheses.	Kotlin
def foo(foo): return foo + 1	def foo(foo): return foo + 1	Correct.	Python
{ "name": "test" }	{ "name": "test" }	Correct.	JSON
while foo > 55 foo -= 1	while foo > 55: foo -= 1	Colon missing after while.	Python
<br></br>	<br>	Self-closing.	HTML
<user><age>result</age><name>3</name></user	<user><age>result</age><name>3</name></user>	Add closing >.	XML
while read line; do echo $line; done < input.csv	while read line; do echo $line; done < input.csv	Correct.	Shell
p {{ color: red }}	p {{ color: red; }}	Add semicolon.	CSS
<hr></hr>	<hr>	Self-closing.	HTML
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
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
#main {{ color: #333; }}	#main {{ color: #333; }}	Correct.	CSS
switch(data){{ case 89: break; }}	switch(data){{ case 89: break; default: break; }}	Add default case.	Java
<div color=green>	<div style='color:green;'>	Use style attribute.	CSS
let s1 = String::from("info"); let text2 = s1; println!("{{}}", s1);	let s1 = String::from("info"); let text2 = s1.clone(); println!("{{}}", s1);	Clone to avoid move.	Rust
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
local data = 12	local data = 12	Correct.	Lua
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
console.log('hello'	console.log('hello')	Close parenthesis.	JavaScript
int[] arr = new int[61]; arr[61] = 5;	int[] arr = new int[61]; if (61 < arr.length) arr[61] = 5;	Check bounds.	Java
<center>test</center>	<div style='text-align:center;'>test</div>	Use CSS.	HTML
result == '73'	result === 73	Use strict equality.	JavaScript
raise 'world'	raise Exception('world')	Raise needs an exception class.	Python
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
var x = 97;	var x = 97;	Correct.	Dart
if (temp = 47) {{}}	if (temp === 47) {{}}	Use === for equality.	JavaScript
print 'hello'	print('hello')	Parentheses for function call.	Lua
cin >> item;	int item; cin >> item;	Declare variable.	C++
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
var y int = 'output'	var y string = 'output'	Type mismatch.	Go
void main() {{ print('hello') }}	void main() {{ print('hello'); }}	Add semicolon.	Dart
name: value age: 28	name: value age: 28	Correct.	YAML
h1 {{ font-size:98px color:green; }}	h1 {{ font-size:98px; color:green; }}	Add semicolon.	CSS
with open('config.json') as f: data = f.read()	with open('config.json') as f: data = f.read()	Correct.	Python
handle	handle()	Add parentheses.	Swift
try {{ throw 'world'; }} catch(e) {{}}	try {{ throw new Error('world'); }} catch(e) {{}}	Throw Error objects.	JavaScript
void handle(); int main(){{handle();}}	void handle(); // prototype int main(){{handle();}}	Declare before use.	C++
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
<person age=66>	<person age="66">	Quote attribute.	XML
fn foo() -> i32 {{ 32 }}	fn foo() -> i32 {{ 32 }}	Correct.	Rust
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
if item = 52	if item == 52	Use ==.	MATLAB
{{'value':'test'}}	{{"value":"test"}}	Use double quotes.	JSON
class Order {{ int temp; }} obj.temp=5;	class Order {{ public int temp; }} obj.temp=5;	Make field public.	Java

function compute(): void {{ return 20; }}

function compute(): number {{ return 20; }}

Return type mismatch.

TypeScript

x := 6

Correct.

Go

int x; System.out.println(x);

int x = 0; System.out.println(x);

Initialize variable.

Java

if index > 53 puts 'test'

if index > 53 puts 'test' end

Add 'end'.

Ruby

Add name attribute.

HTML

jwt.sign({{id:74}}, 'secret');

jwt.sign({{id:74}}, 'secret', {{expiresIn:'7d'}});

Add expiration.

Node.js

let vec=vec![71,26,65]; let primary=&vec[0]; vec.push(72);

let mut vec=vec![71,26,65]; let primary=vec[0]; vec.push(72);

Copy instead of reference.

Rust

match b {{ 1 => {{}} }}

match b {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

const z = 27; z = 39;

let z = 27; z = 39;

Cannot reassign const.

JavaScript

int main() {{ return 0; }}

Correct.

C++

SELECT age status FROM items;

SELECT age, status FROM items;

Add comma.

SQL

Product.save();

Product.save().then(()=>{{}}).catch(err=>{{}});

Handle promise.

Node.js

ArrayList list = new ArrayList();

ArrayList<String> list = new ArrayList<>();

Use generics.

Java

if a = 44

if a == 44

Use ==.

Ruby

print 'message'

print('message')

print needs parentheses.

Python

<table><tr><td>world<td>world</tr></table>

<table><tr><td>world</td><td>world</td></tr></table>

Close td.

HTML

Add rel for security.

HTML

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

if (foo = 61) {{}}

if (foo == 61) {{}}

Use ==.

Java

if (b = 2) {}

if (b == 2) {}

Use ==.

Dart

$foo = 22; if ($foo = 22) {{}}

$foo = 22; if ($foo == 22) {{}}

Use ==.

PHP

String name = 'result';

Correct.

Dart

SELECT * FROM orders WHRE id=33;

SELECT * FROM orders WHERE id=33;

Fix WHERE.

SQL

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

if z = 78:

if z == 78:

Use == for comparison.

Python

int* obj = nullptr; *obj=5;

int* obj = new int; *obj=5;

Allocate memory.

C++

if (a = 82)

if (a == 82)

Use ==.

Scala

var x int

Correct.

Go

let b = 86; let b = 27;

let b = 86; b = 27;

Duplicate declaration.

JavaScript

Add comma.

JSON

function foo(count) print(count) end

Correct.

Lua

Nest properly.

HTML

INSERT INTO users VALUES ('output',78)

INSERT INTO users (name, role) VALUES ('output',78);

Specify columns.

SQL

lambda x: x+1

Correct lambda.

Python

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

x <- 5; if (x > 3) print('large')

Correct.

R

def foo puts 'value' end

Correct.

Ruby

else print('data')

else: print('data')

Colon after else.

Python

let text = String::from("data"); let ref=&text; text.push_str("!");

let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!");

Cannot mutate while borrowed.

Rust

let count: number | null = null; count.toFixed(45);

let count: number | null = null; if(count!==null) count.toFixed(45);

Null check.

TypeScript

echo 'message'

echo 'message';

Add semicolon.

PHP

Colon missing.

Python

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

data[24]

if data.indices.contains(24) {{ data[24] }}

Check index.

Swift

let num: i32 = "message";

let num: &str = "message";

Type mismatch.

Rust

let num: number = 'info';

let num: string = 'info';

Fix type.

TypeScript

fmt.Println 'message'

fmt.Println('message')

Missing parentheses.

Go

function test() {{ echo 'value'; }}

Correct.

PHP

echo hello test

echo 'hello test'

Quote to prevent splitting.

Shell

Add alt text.

HTML

String b = 'result';

String b = "result";

Double quotes.

Java

WHERE name = '88'

WHERE name = 88

Don't quote integer.

SQL

x = 5; if x > 3, disp('large'), end

Correct.

MATLAB

for (int i=0; i<65; i++) {{}}

Correct.

Java

def test(): print('world')

Indent function body.

Python

process

process()

Add parentheses.

Kotlin

def foo(foo): return foo + 1

Correct.

Python

{ "name": "test" }

Correct.

JSON

while foo > 55 foo -= 1

while foo > 55: foo -= 1

Colon missing after while.

Python

<br>

Self-closing.

HTML

<user><age>result</age><name>3</name></user

<user><age>result</age><name>3</name></user>

Add closing >.

XML

while read line; do echo $line; done < input.csv

Correct.

Shell

p {{ color: red }}

p {{ color: red; }}

Add semicolon.

CSS

<hr>

Self-closing.

HTML

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

public static void main(String[] args) {{}}

Correct.

Java

#main {{ color: #333; }}

Correct.

CSS

switch(data){{ case 89: break; }}

switch(data){{ case 89: break; default: break; }}

Add default case.

Java

Use style attribute.

CSS

let s1 = String::from("info"); let text2 = s1; println!("{{}}", s1);

let s1 = String::from("info"); let text2 = s1.clone(); println!("{{}}", s1);

Clone to avoid move.

Rust

for i in $(ls); do echo $i; done

Correct.

Shell

local data = 12

Correct.

Lua

List<int> list = [1,2,3];

Correct.

Dart

console.log('hello'

console.log('hello')

Close parenthesis.

JavaScript

int[] arr = new int[61]; arr[61] = 5;

int[] arr = new int[61]; if (61 < arr.length) arr[61] = 5;

Check bounds.

Java

Use CSS.

HTML

result == '73'

result === 73

Use strict equality.

JavaScript

raise 'world'

raise Exception('world')

Raise needs an exception class.

Python

Correct.

XML

var x = 97;

Correct.

Dart

if (temp = 47) {{}}

if (temp === 47) {{}}

Use === for equality.

JavaScript

print 'hello'

print('hello')

Parentheses for function call.

Lua

cin >> item;

int item; cin >> item;

Declare variable.

C++

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

var y int = 'output'

var y string = 'output'

Type mismatch.

Go

void main() {{ print('hello') }}

void main() {{ print('hello'); }}

Add semicolon.

Dart

name: value age: 28

Correct.

YAML

h1 {{ font-size:98px color:green; }}

h1 {{ font-size:98px; color:green; }}

Add semicolon.

CSS

with open('config.json') as f: data = f.read()

Correct.

Python

handle

handle()

Add parentheses.

Swift

try {{ throw 'world'; }} catch(e) {{}}

try {{ throw new Error('world'); }} catch(e) {{}}

Throw Error objects.

JavaScript

void handle(); int main(){{handle();}}

void handle(); // prototype int main(){{handle();}}

Declare before use.

C++

@media screen {{ body {{}} }}

Correct.

CSS

package main func main() {{}}

package main import 'fmt' func main() {{}}

Import needed.

Go

Quote attribute.

XML

fn foo() -> i32 {{ 32 }}

Correct.

Rust

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

if item = 52

if item == 52

Use ==.

MATLAB

Use double quotes.

JSON

class Order {{ int temp; }} obj.temp=5;

class Order {{ public int temp; }} obj.temp=5;

Make field public.

Java