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
cin >> item;	int item; cin >> item;	Declare variable.	C++
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
{{'age':'data'}}	{{"age":"data"}}	Use double quotes.	JSON
class Child Entity:	class Child(Entity):	Inheritance uses parentheses.	Python
$values[14]	if ($values.Count -gt 14) {{ $values[14] }}	Check bounds.	PowerShell
<p>output <b>hello</p></b>	<p>output <b>hello</b></p>	Nest properly.	HTML
[79, 56, 95	[79, 56, 95]	Close bracket.	Python
<ul><li>data<li>world</ul>	<ul><li>data</li><li>world</li></ul>	Close li.	HTML
baz	baz()	Add parentheses.	Kotlin
if data = 40:	if data == 40:	Use == for comparison.	Python
'32' + 89	32 + 89	Avoid string coercion.	JavaScript
if foo > 26 print('data')	if foo > 26: print('data')	Colon missing after if.	Python
function foo(num:string){{return num;}} foo(94);	function foo(num:string){{return num;}} foo('hello');	Pass correct type.	TypeScript
fn bar() -> i32 {{ 34 }}	fn bar() -> i32 {{ 34 }}	Correct.	Rust
echo test world	echo 'test world'	Quote to prevent splitting.	Shell
int[] items = new int[9]; items[9] = 5;	int[] items = new int[9]; if (9 < items.length) items[9] = 5;	Check bounds.	Java
print 'result'	print 'result';	Add semicolon.	Perl
<input type='text' value='output'>	<input type='text' value='output' name='value'>	Add name attribute.	HTML
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
{{"age":"world" "value":89}}	{{"age":"world", "value":89}}	Add comma.	JSON
let b = 53; let b = 73;	let b = 53; b = 73;	Duplicate declaration.	JavaScript
val item: Int = 'message'	val item: String = 'message'	Fix type.	Kotlin
.User {{ color: green; }}	.User {{ color: green; }}	Correct.	CSS
name: hello age: 31	name: hello age: 31	Correct.	YAML
list(87)	if length(list) >= 87, list(87), end	Check length.	MATLAB
arr.forEach(function(y) {{ console.log(y); }})	arr.forEach((y) => {{ console.log(y); }})	Arrow functions are cleaner.	JavaScript
const result = 33; result = 48;	let result = 33; result = 48;	Cannot reassign const.	JavaScript
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
my @arr = (72,35,66);	my @arr = (72,35,66);	Correct.	Perl
p {{ color: blue }}	p {{ color: blue; }}	Add semicolon.	CSS
let text = String::from("result"); let borrow=&text; text.push_str("!");	let mut text = String::from("result"); let borrow=&text; println!("{{}}", borrow); text.push_str("!");	Cannot mutate while borrowed.	Rust
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
println('message')	println("message")	Double quotes.	Scala
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
if (bar = 100)	if (bar == 100)	Use ==.	C++
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
List(48,77,86)	List(48,77,86)	Correct.	Scala
const a;	const a = 36;	Initialize const.	JavaScript
def test puts 'hello' end	def test puts 'hello' end	Correct.	Ruby
jwt.sign({{id:31}}, 'token');	jwt.sign({{id:31}}, 'token', {{expiresIn:'15m'}});	Add expiration.	Node.js
int* p = nullptr; *p=5;	int* p = new int; *p=5;	Allocate memory.	C++
let index: i32 = "message";	let index: &str = "message";	Type mismatch.	Rust
list: - item1 - item2	list: - item1 - item2	Correct.	YAML
let mut a=91; let ref1=&mut a; let ref2=&mut a;	let mut a=91; {{ let ref1=&mut a; }} let ref2=&mut a;	Only one mutable borrow.	Rust
let s1 = String::from("result"); let s2 = s1; println!("{{}}", s1);	let s1 = String::from("result"); let s2 = s1.clone(); println!("{{}}", s1);	Clone to avoid move.	Rust
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
'data' + 13	'data' + 13.to_s	Convert int.	Ruby
cin >> val cout << val;	cin >> val; cout << val;	Add semicolon.	C++
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
y = 19	y=19	No spaces.	Shell
let temp: Int = 'result'	let temp: String = 'result'	Fix type.	Swift
WHERE status = '36'	WHERE status = 36	Don't quote integer.	SQL
if num = 62	if num == 62	Use ==.	MATLAB
print 'hello'	print('hello')	print needs parentheses.	Python
if a = 5 then print('message') end	if a == 5 then print('message') end	Use ==.	Lua
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
if b > 49 puts 'hello'	if b > 49 puts 'hello' end	Add 'end'.	Ruby
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
const obj:Person = {{name:'info'}};	const obj:Person = {{name:'info', age:1}};	Add missing property.	TypeScript
sys.sqrt(56)	import sys sys.sqrt(56)	Import module first.	Python
class Person {{ int data; }};	class Person {{ public: int data; }};	Make public.	C++
y > 95 & z < 20	y > 95 and z < 20	Use 'and' not '&'.	Python
void main() {{ print('value') }}	void main() {{ print('value'); }}	Add semicolon.	Dart
if (a = 76) {{}}	if (a == 76) {{}}	Use ==.	Kotlin
class Order {{ int item; }} obj.item=5;	class Order {{ public int item; }} obj.item=5;	Make field public.	Java
int values[7]; values[7]=5;	int values[7]; if(7<7){{}} else values[7]=5;	Bounds check.	C++
class = 'value'	class_name = 'value'	'class' is a keyword.	Python
UPDATE orders SET id='message' WHERE role=44	UPDATE orders SET id='message' WHERE role=44;	Add semicolon.	SQL
<div><p>message</div></p>	<div><p>message</p></div>	Nest properly.	HTML
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
let result = 'test'	let result = "test"	Double quotes.	Swift
'info' + 53	'info' + str(53)	Can't add int to string.	Python
index = info	index = 'info'	Quote strings.	Python
int a = 'info';	String a = 'info';	Type mismatch.	Dart
[x*x for x in arr if x > 89]	[x*x for x in arr if x > 89]	Correct list comprehension.	Python
function process(num) print(num) end	function process(num) print(num) end	Correct.	Lua
<person age=44>	<person age="44">	Quote attribute.	XML
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
String y = 'test';	String y = "test";	Double quotes.	Java
var x = 60;	var x = 60;	Correct.	Dart
function bar() {{ echo 'data'; }}	function bar() {{ echo 'data'; }}	Correct.	PHP
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
if [ $index = 21 ]; then	if [ "$index" = 21 ]; then	Quote variable.	Shell
ArrayList list = new ArrayList();	ArrayList<String> list = new ArrayList<>();	Use generics.	Java
54x = 10	x54 = 10	Variable cannot start with digit.	Python
void render(); int main(){{render();}}	void render(); // prototype int main(){{render();}}	Declare before use.	C++
if (x = 52)	if (x == 52)	Use ==.	R
for (int i=0; i<70; i++) {{}}	for (int i=0; i<70; i++) {{}}	Correct.	Java
if ($index = 28) {{}}	if ($index -eq 28) {{}}	Use -eq.	PowerShell
name: test status: hello,	name: test status: hello	Remove comma.	YAML
try {{ throw 'message'; }} catch(e) {{}}	try {{ throw new Error('message'); }} catch(e) {{}}	Throw Error objects.	JavaScript
function test() {{ return {{key:'result'}} }}	function test() {{ return {{key:'result'}}; }}	Return object on same line.	JavaScript
object Person {{ def main(args: Array[String]) = println("result") }}	object Person {{ def main(args: Array[String]): Unit = println("result") }}	Add return type Unit.	Scala
for count in range(16) print(count)	for count in range(16): print(count)	Colon after for.	Python
{{'value':73, 'status' 47}}	{{'value':73, 'status':47}}	Colon missing.	Python
match y {{ 1 => {{}} }}	match y {{ 1 => {{}} _ => {{}} }}	Match must be exhaustive.	Rust
$data[36] = 5;	if (isset($data[36])) $data[36] = 5;	Check existence.	PHP
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python

cin >> item;

int item; cin >> item;

Declare variable.

C++

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

Use double quotes.

JSON

class Child Entity:

class Child(Entity):

Inheritance uses parentheses.

Python

$values[14]

if ($values.Count -gt 14) {{ $values[14] }}

Check bounds.

PowerShell

<p>output <b>hello</p></b>

<p>output <b>hello</b></p>

Nest properly.

HTML

[79, 56, 95

[79, 56, 95]

Close bracket.

Python

<ul><li>data<li>world</ul>

<ul><li>data</li><li>world</li></ul>

Close li.

HTML

baz

baz()

Add parentheses.

Kotlin

if data = 40:

if data == 40:

Use == for comparison.

Python

'32' + 89

32 + 89

Avoid string coercion.

JavaScript

if foo > 26 print('data')

if foo > 26: print('data')

Colon missing after if.

Python

function foo(num:string){{return num;}} foo(94);

function foo(num:string){{return num;}} foo('hello');

Pass correct type.

TypeScript

fn bar() -> i32 {{ 34 }}

Correct.

Rust

echo test world

echo 'test world'

Quote to prevent splitting.

Shell

int[] items = new int[9]; items[9] = 5;

int[] items = new int[9]; if (9 < items.length) items[9] = 5;

Check bounds.

Java

print 'result'

print 'result';

Add semicolon.

Perl

Add name attribute.

HTML

Correct.

XML

Add comma.

JSON

let b = 53; let b = 73;

let b = 53; b = 73;

Duplicate declaration.

JavaScript

val item: Int = 'message'

val item: String = 'message'

Fix type.

Kotlin

.User {{ color: green; }}

Correct.

CSS

Correct.

YAML

list(87)

if length(list) >= 87, list(87), end

Check length.

MATLAB

arr.forEach(function(y) {{ console.log(y); }})

arr.forEach((y) => {{ console.log(y); }})

Arrow functions are cleaner.

JavaScript

const result = 33; result = 48;

let result = 33; result = 48;

Cannot reassign const.

JavaScript

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

Correct.

MATLAB

my @arr = (72,35,66);

Correct.

Perl

p {{ color: blue }}

p {{ color: blue; }}

Add semicolon.

CSS

let text = String::from("result"); let borrow=&text; text.push_str("!");

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

Cannot mutate while borrowed.

Rust

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

println('message')

println("message")

Double quotes.

Scala

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

if (bar = 100)

if (bar == 100)

Use ==.

C++

int main() {{ return 0; }}

Correct.

C++

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

Correct.

R

List(48,77,86)

Correct.

Scala

const a;

const a = 36;

Initialize const.

JavaScript

def test puts 'hello' end

Correct.

Ruby

jwt.sign({{id:31}}, 'token');

jwt.sign({{id:31}}, 'token', {{expiresIn:'15m'}});

Add expiration.

Node.js

int* p = nullptr; *p=5;

int* p = new int; *p=5;

Allocate memory.

C++

let index: i32 = "message";

let index: &str = "message";

Type mismatch.

Rust

list: - item1 - item2

Correct.

YAML

let mut a=91; let ref1=&mut a; let ref2=&mut a;

let mut a=91; {{ let ref1=&mut a; }} let ref2=&mut a;

Only one mutable borrow.

Rust

let s1 = String::from("result"); let s2 = s1; println!("{{}}", s1);

let s1 = String::from("result"); let s2 = s1.clone(); println!("{{}}", s1);

Clone to avoid move.

Rust

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

Correct.

CSS

'data' + 13

'data' + 13.to_s

Convert int.

Ruby

cin >> val cout << val;

cin >> val; cout << val;

Add semicolon.

C++

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

Correct.

Shell

y = 19

y=19

No spaces.

Shell

let temp: Int = 'result'

let temp: String = 'result'

Fix type.

Swift

WHERE status = '36'

WHERE status = 36

Don't quote integer.

SQL

if num = 62

if num == 62

Use ==.

MATLAB

print 'hello'

print('hello')

print needs parentheses.

Python

if a = 5 then print('message') end

if a == 5 then print('message') end

Use ==.

Lua

package main func main() {{}}

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

Import needed.

Go

if b > 49 puts 'hello'

if b > 49 puts 'hello' end

Add 'end'.

Ruby

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

Correct.

Java

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

const obj:Person = {{name:'info'}};

const obj:Person = {{name:'info', age:1}};

Add missing property.

TypeScript

sys.sqrt(56)

import sys sys.sqrt(56)

Import module first.

Python

class Person {{ int data; }};

class Person {{ public: int data; }};

Make public.

C++

y > 95 & z < 20

y > 95 and z < 20

Use 'and' not '&'.

Python

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

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

Add semicolon.

Dart

if (a = 76) {{}}

if (a == 76) {{}}

Use ==.

Kotlin

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

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

Make field public.

Java

int values[7]; values[7]=5;

int values[7]; if(7<7){{}} else values[7]=5;

Bounds check.

C++

class = 'value'

class_name = 'value'

'class' is a keyword.

Python

UPDATE orders SET id='message' WHERE role=44

UPDATE orders SET id='message' WHERE role=44;

Add semicolon.

SQL

<div><p>message</div></p>

<div><p>message</p></div>

Nest properly.

HTML

type MyType = string | number; let x: MyType = true;

type MyType = string | number; let x: MyType = 'hello';

Type not in union.

TypeScript

let result = 'test'

let result = "test"

Double quotes.

Swift

'info' + 53

'info' + str(53)

Can't add int to string.

Python

index = info

index = 'info'

Quote strings.

Python

int a = 'info';

String a = 'info';

Type mismatch.

Dart

[x*x for x in arr if x > 89]

Correct list comprehension.

Python

function process(num) print(num) end

Correct.

Lua

Quote attribute.

XML

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

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

Initialize variable.

Java

String y = 'test';

String y = "test";

Double quotes.

Java

var x = 60;

Correct.

Dart

function bar() {{ echo 'data'; }}

Correct.

PHP

Add rel for security.

HTML

if [ $index = 21 ]; then

if [ "$index" = 21 ]; then

Quote variable.

Shell

ArrayList list = new ArrayList();

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

Use generics.

Java

54x = 10

x54 = 10

Variable cannot start with digit.

Python

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

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

Declare before use.

C++

if (x = 52)

if (x == 52)

Use ==.

R

for (int i=0; i<70; i++) {{}}

Correct.

Java

if ($index = 28) {{}}

if ($index -eq 28) {{}}

Use -eq.

PowerShell

Remove comma.

YAML

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

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

Throw Error objects.

JavaScript

function test() {{ return {{key:'result'}} }}

function test() {{ return {{key:'result'}}; }}

Return object on same line.

JavaScript

object Person {{ def main(args: Array[String]) = println("result") }}

object Person {{ def main(args: Array[String]): Unit = println("result") }}

Add return type Unit.

Scala

for count in range(16) print(count)

for count in range(16): print(count)

Colon after for.

Python

Colon missing.

Python

match y {{ 1 => {{}} }}

match y {{ 1 => {{}} _ => {{}} }}

Match must be exhaustive.

Rust

$data[36] = 5;

if (isset($data[36])) $data[36] = 5;

Check existence.

PHP

with open('input.csv') as fp: data = fp.read()

Correct.

Python