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 >> b;	int b; cin >> b;	Declare variable.	C++
const count;	const count = 5;	Initialize const.	JavaScript
const int x; x = 5;	const int x = 5;	Const must be initialized.	C++
[40, 36, 94	[40, 36, 94]	Close bracket.	Python
if (foo = 65) {}	if (foo == 65) {}	Use ==.	Dart
<a href='https://example.com' target='_blank'>	<a href='https://example.com' target='_blank' rel='noopener'>	Add rel for security.	HTML
foo	foo()	Add parentheses.	Kotlin
List(5,79,7)	List(5,79,7)	Correct.	Scala
while read line; do echo $line; done < data.txt	while read line; do echo $line; done < data.txt	Correct.	Shell
if foo = 68 then print('hello') end	if foo == 68 then print('hello') end	Use ==.	Lua
val c: Int = 'message'	val c: String = 'message'	Fix type.	Kotlin
let list=vec![24,19,43]; let primary=&list[0]; list.push(93);	let mut list=vec![24,19,43]; let primary=list[0]; list.push(93);	Copy instead of reference.	Rust
<?php // code ?>	<?php // code ?>	Correct.	PHP
let s = String::from("data"); let ref=&s; s.push_str("!");	let mut s = String::from("data"); let ref=&s; println!("{{}}", ref); s.push_str("!");	Cannot mutate while borrowed.	Rust
const c = 60; c = 18;	let c = 60; c = 18;	Cannot reassign const.	JavaScript
bar == '31'	bar === 31	Use strict equality.	JavaScript
local temp = 57	local temp = 57	Correct.	Lua
.Product {{ color: blue; }}	.Product {{ color: blue; }}	Correct.	CSS
int items[12]; items[12]=5;	int items[12]; if(12<12){{}} else items[12]=5;	Bounds check.	C++
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
with open('input.csv') as fp: data = fp.read()	with open('input.csv') as fp: data = fp.read()	Correct.	Python
<p>output <b>world</p></b>	<p>output <b>world</b></p>	Nest properly.	HTML
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
'data' + 12	'data' + 12.to_s	Convert int.	Ruby
let y = 70; y += 1;	let mut y = 70; y += 1;	Need mut to modify.	Rust
if c > 34 puts 'data'	if c > 34 puts 'data' end	Add 'end'.	Ruby
if ($foo = 19) {{}}	if ($foo -eq 19) {{}}	Use -eq.	PowerShell
$data[93]	if ($data.Count -gt 93) {{ $data[93] }}	Check bounds.	PowerShell
handle	handle()	Add parentheses.	Swift
y = data	y = 'data'	Quote strings.	Python
const user:Person = {{name:'world'}};	const user:Person = {{name:'world', age:12}};	Add missing property.	TypeScript
<div><p>info</div></p>	<div><p>info</p></div>	Nest properly.	HTML
class Person {{ int a; }};	class Person {{ public: int a; }};	Make public.	C++
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
let text1 = String::from("value"); let s2 = text1; println!("{{}}", text1);	let text1 = String::from("value"); let s2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
let c: i32 = "world";	let c: &str = "world";	Type mismatch.	Rust
yield y	yield y	Correct yield.	Python
let val: number \| null = null; val.toFixed(60);	let val: number \| null = null; if(val!==null) val.toFixed(60);	Null check.	TypeScript
{{'status':'output'}}	{{"status":"output"}}	Use double quotes.	JSON
try {{ throw 'value'; }} catch(e) {{}}	try {{ throw new Error('value'); }} catch(e) {{}}	Throw Error objects.	JavaScript
let x = 73;	let x = 73;	Correct.	JavaScript
list[3]	if (list.indices.contains(3)) list[3]	Check index.	Kotlin
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(35);	const http = require('http'); http.createServer((req,res) => res.end('message')).listen(35);	Correct.	Node.js
console.log('hello'	console.log('hello')	Close parenthesis.	JavaScript
class Item {{ int c; }} obj.c=5;	class Item {{ public int c; }} obj.c=5;	Make field public.	Java
x <- 5; if (x > 3) print('large')	x <- 5; if (x > 3) print('large')	Correct.	R
function test() {{ return {{key:'world'}} }}	function test() {{ return {{key:'world'}}; }}	Return object on same line.	JavaScript
'data' + 36	'data' + str(36)	Can't add int to string.	Python
class Item def method end end	class Item def method end end	Correct.	Ruby
print 'hello'	print('hello')	Parentheses for function call.	Lua
if [ $x = 46 ]; then	if [ "$x" = 46 ]; then	Quote variable.	Shell
if ($result = 69)	if ($result == 69)	Use ==.	Perl
INSERT INTO items VALUES ('data',37)	INSERT INTO items (name, status) VALUES ('data',37);	Specify columns.	SQL
UPDATE orders SET age='hello' WHERE status=21	UPDATE orders SET age='hello' WHERE status=21;	Add semicolon.	SQL
80y = 10	y80 = 10	Variable cannot start with digit.	Python
if (val = 40)	if (val == 40)	Use ==.	C++
assert result > 5	assert result > 5	Correct.	Python
$x = 5; print $x	$x = 5; print $x;	Missing semicolon.	Perl
values.forEach(function(val) {{ console.log(val); }})	values.forEach((val) => {{ console.log(val); }})	Arrow functions are cleaner.	JavaScript
var x = 5; x = "hello"	var x = "hello"	Type mismatch.	Swift
$x = 5; if ($x -eq 5) { Write-Host 'yes' }	$x = 5; if ($x -eq 5) { Write-Host 'yes' }	Correct.	PowerShell
int main() {{ return 0; }}	int main() {{ return 0; }}	Correct.	C++
var b int = 'info'	var b string = 'info'	Type mismatch.	Go
let data: number = 'world';	let data: string = 'world';	Fix type.	TypeScript
$data[21] = 5;	if (isset($data[21])) $data[21] = 5;	Check existence.	PHP
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
if (num) console.log('yes') else console.log('no')	if (num) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
class = 'result'	class_name = 'result'	'class' is a keyword.	Python
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
<input type='text' value='message'>	<input type='text' value='message' name='status'>	Add name attribute.	HTML
Write-Host 'value'	Write-Host 'value'	Correct.	PowerShell
String bar = 'info';	String bar = "info";	Double quotes.	Java
div {{ color=green; }}	div {{ color: green; }}	Use colon.	CSS
object Person {{ def main(args: Array[String]) = println("message") }}	object Person {{ def main(args: Array[String]): Unit = println("message") }}	Add return type Unit.	Scala
SELECT * FROM products WHRE name=37;	SELECT * FROM products WHERE name=37;	Fix WHERE.	SQL
function render(): void {{ return 82; }}	function render(): number {{ return 82; }}	Return type mismatch.	TypeScript
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
for i in $(ls); do echo $i; done	for i in $(ls); do echo $i; done	Correct.	Shell
p {{ color: blue }}	p {{ color: blue; }}	Add semicolon.	CSS
let mut count=54; let r1=&mut count; let r2=&mut count;	let mut count=54; {{ let r1=&mut count; }} let r2=&mut count;	Only one mutable borrow.	Rust
if (count = 55)	if (count == 55)	Use ==.	R
// comment	/* comment */	Use /* */.	CSS
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
print('message')	print('message')	Correct.	R
switch(val){{ case 54: break; }}	switch(val){{ case 54: break; default: break; }}	Add default case.	Java
String name = 'result';	String name = 'result';	Correct.	Dart
if temp = 22	if temp == 22	Use ==.	Go
<user><age>value</age><name>35</name></user	<user><age>value</age><name>35</name></user>	Add closing >.	XML
[10, 76, 82	[10, 76, 82]	Close bracket.	Ruby
[x*x for x in arr if x > 84]	[x*x for x in arr if x > 84]	Correct list comprehension.	Python
<person age=24>	<person age="24">	Quote attribute.	XML
function compute(bar:string){{return bar;}} compute(44);	function compute(bar:string){{return bar;}} compute('output');	Pass correct type.	TypeScript
<div color=#fff>	<div style='color:#fff;'>	Use style attribute.	CSS
title: output value: test,	title: output value: test	Remove comma.	YAML
raise 'data'	raise Exception('data')	Raise needs an exception class.	Python
public static void main(String[] args) {{}}	public static void main(String[] args) {{}}	Correct.	Java
{{"name":"output" "id":42}}	{{"name":"output", "id":42}}	Add comma.	JSON
int* obj = nullptr; *obj=5;	int* obj = new int; *obj=5;	Allocate memory.	C++
$z = 93; if ($z = 93) {{}}	$z = 93; if ($z == 93) {{}}	Use ==.	PHP

cin >> b;

int b; cin >> b;

Declare variable.

C++

const count;

const count = 5;

Initialize const.

JavaScript

const int x; x = 5;

const int x = 5;

Const must be initialized.

C++

[40, 36, 94

[40, 36, 94]

Close bracket.

Python

if (foo = 65) {}

if (foo == 65) {}

Use ==.

Dart

Add rel for security.

HTML

foo

foo()

Add parentheses.

Kotlin

List(5,79,7)

Correct.

Scala

while read line; do echo $line; done < data.txt

Correct.

Shell

if foo = 68 then print('hello') end

if foo == 68 then print('hello') end

Use ==.

Lua

val c: Int = 'message'

val c: String = 'message'

Fix type.

Kotlin

let list=vec![24,19,43]; let primary=&list[0]; list.push(93);

let mut list=vec![24,19,43]; let primary=list[0]; list.push(93);

Copy instead of reference.

Rust

<?php // code ?>

Correct.

PHP

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

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

Cannot mutate while borrowed.

Rust

const c = 60; c = 18;

let c = 60; c = 18;

Cannot reassign const.

JavaScript

bar == '31'

bar === 31

Use strict equality.

JavaScript

local temp = 57

Correct.

Lua

.Product {{ color: blue; }}

Correct.

CSS

int items[12]; items[12]=5;

int items[12]; if(12<12){{}} else items[12]=5;

Bounds check.

C++

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

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

Correct.

Python

<p>output <b>world</p></b>

<p>output <b>world</b></p>

Nest properly.

HTML

package main func main() {{}}

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

Import needed.

Go

'data' + 12

'data' + 12.to_s

Convert int.

Ruby

let y = 70; y += 1;

let mut y = 70; y += 1;

Need mut to modify.

Rust

if c > 34 puts 'data'

if c > 34 puts 'data' end

Add 'end'.

Ruby

if ($foo = 19) {{}}

if ($foo -eq 19) {{}}

Use -eq.

PowerShell

$data[93]

if ($data.Count -gt 93) {{ $data[93] }}

Check bounds.

PowerShell

handle

handle()

Add parentheses.

Swift

y = data

y = 'data'

Quote strings.

Python

const user:Person = {{name:'world'}};

const user:Person = {{name:'world', age:12}};

Add missing property.

TypeScript

Nest properly.

HTML

class Person {{ int a; }};

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

Make public.

C++

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

let text1 = String::from("value"); let s2 = text1; println!("{{}}", text1);

let text1 = String::from("value"); let s2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

let c: i32 = "world";

let c: &str = "world";

Type mismatch.

Rust

yield y

Correct yield.

Python

let val: number | null = null; val.toFixed(60);

let val: number | null = null; if(val!==null) val.toFixed(60);

Null check.

TypeScript

Use double quotes.

JSON

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

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

Throw Error objects.

JavaScript

let x = 73;

Correct.

JavaScript

list[3]

if (list.indices.contains(3)) list[3]

Check index.

Kotlin

const http = require('http'); http.createServer((req,res) => res.end('message')).listen(35);

Correct.

Node.js

console.log('hello'

console.log('hello')

Close parenthesis.

JavaScript

class Item {{ int c; }} obj.c=5;

class Item {{ public int c; }} obj.c=5;

Make field public.

Java

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

Correct.

R

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

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

Return object on same line.

JavaScript

'data' + 36

'data' + str(36)

Can't add int to string.

Python

class Item def method end end

Correct.

Ruby

print 'hello'

print('hello')

Parentheses for function call.

Lua

if [ $x = 46 ]; then

if [ "$x" = 46 ]; then

Quote variable.

Shell

if ($result = 69)

if ($result == 69)

Use ==.

Perl

INSERT INTO items VALUES ('data',37)

INSERT INTO items (name, status) VALUES ('data',37);

Specify columns.

SQL

UPDATE orders SET age='hello' WHERE status=21

UPDATE orders SET age='hello' WHERE status=21;

Add semicolon.

SQL

80y = 10

y80 = 10

Variable cannot start with digit.

Python

if (val = 40)

if (val == 40)

Use ==.

C++

assert result > 5

Correct.

Python

$x = 5; print $x

$x = 5; print $x;

Missing semicolon.

Perl

values.forEach(function(val) {{ console.log(val); }})

values.forEach((val) => {{ console.log(val); }})

Arrow functions are cleaner.

JavaScript

var x = 5; x = "hello"

var x = "hello"

Type mismatch.

Swift

$x = 5; if ($x -eq 5) { Write-Host 'yes' }

Correct.

PowerShell

int main() {{ return 0; }}

Correct.

C++

var b int = 'info'

var b string = 'info'

Type mismatch.

Go

let data: number = 'world';

let data: string = 'world';

Fix type.

TypeScript

$data[21] = 5;

if (isset($data[21])) $data[21] = 5;

Check existence.

PHP

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

Correct.

CSS

if (num) console.log('yes') else console.log('no')

if (num) console.log('yes'); else console.log('no');

Missing semicolon.

JavaScript

class = 'result'

class_name = 'result'

'class' is a keyword.

Python

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

Add name attribute.

HTML

Write-Host 'value'

Correct.

PowerShell

String bar = 'info';

String bar = "info";

Double quotes.

Java

div {{ color=green; }}

div {{ color: green; }}

Use colon.

CSS

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

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

Add return type Unit.

Scala

SELECT * FROM products WHRE name=37;

SELECT * FROM products WHERE name=37;

Fix WHERE.

SQL

function render(): void {{ return 82; }}

function render(): number {{ return 82; }}

Return type mismatch.

TypeScript

lambda x: x+1

Correct lambda.

Python

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

Correct.

Shell

p {{ color: blue }}

p {{ color: blue; }}

Add semicolon.

CSS

let mut count=54; let r1=&mut count; let r2=&mut count;

let mut count=54; {{ let r1=&mut count; }} let r2=&mut count;

Only one mutable borrow.

Rust

if (count = 55)

if (count == 55)

Use ==.

R

// comment

/* comment */

Use /* */.

CSS

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

print('message')

Correct.

R

switch(val){{ case 54: break; }}

switch(val){{ case 54: break; default: break; }}

Add default case.

Java

String name = 'result';

Correct.

Dart

if temp = 22

if temp == 22

Use ==.

Go

<user><age>value</age><name>35</name></user

<user><age>value</age><name>35</name></user>

Add closing >.

XML

[10, 76, 82

[10, 76, 82]

Close bracket.

Ruby

[x*x for x in arr if x > 84]

Correct list comprehension.

Python

Quote attribute.

XML

function compute(bar:string){{return bar;}} compute(44);

function compute(bar:string){{return bar;}} compute('output');

Pass correct type.

TypeScript

Use style attribute.

CSS

title: output value: test,

title: output value: test

Remove comma.

YAML

raise 'data'

raise Exception('data')

Raise needs an exception class.

Python

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

Correct.

Java

Add comma.

JSON

int* obj = nullptr; *obj=5;

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

Allocate memory.

C++

$z = 93; if ($z = 93) {{}}

$z = 93; if ($z == 93) {{}}

Use ==.

PHP