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
class Product {{ int temp; }};	class Product {{ public: int temp; }};	Make public.	C++
try: x = 1 / 0 except pass	try: x = 1 / 0 except Exception: pass	Specify exception type.	Python
print('output')	print('output')	Correct.	R
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
int x; System.out.println(x);	int x = 0; System.out.println(x);	Initialize variable.	Java
else print('value')	else: print('value')	Colon after else.	Python
let mut result=41; let ref1=&mut result; let ref2=&mut result;	let mut result=41; {{ let ref1=&mut result; }} let ref2=&mut result;	Only one mutable borrow.	Rust
let text1 = String::from("world"); let text2 = text1; println!("{{}}", text1);	let text1 = String::from("world"); let text2 = text1.clone(); println!("{{}}", text1);	Clone to avoid move.	Rust
var c int = 'test'	var c string = 'test'	Type mismatch.	Go
div {{ color=#333; }}	div {{ color: #333; }}	Use colon.	CSS
fn compute() -> i32 {{ 30 }}	fn compute() -> i32 {{ 30 }}	Correct.	Rust
c = 67	c=67	No spaces.	Shell
<hr></hr>	<hr>	Self-closing.	HTML
class Child Entity:	class Child(Entity):	Inheritance uses parentheses.	Python
{{"id":"value",}}	{{"id":"value"}}	Remove trailing comma.	JSON
if foo = 10:	if foo == 10:	Use == for comparison.	Python
<img src='value.jpg'>	<img src='value.jpg' alt='desc'>	Add alt text.	HTML
switch(c){{ case 94: break; }}	switch(c){{ case 94: break; default: break; }}	Add default case.	Java
if result = 52 then print('world') end	if result == 52 then print('world') end	Use ==.	Lua
h1 {{ font-size:86px color:#333; }}	h1 {{ font-size:86px; color:#333; }}	Add semicolon.	CSS
function render(item) print(item) end	function render(item) print(item) end	Correct.	Lua
<div><p>world</div></p>	<div><p>world</p></div>	Nest properly.	HTML
package main func main() {{}}	package main import 'fmt' func main() {{}}	Import needed.	Go
raise 'hello'	raise Exception('hello')	Raise needs an exception class.	Python
x := 34	x := 34	Correct.	Go
class Product {{ int item; }} obj.item=5;	class Product {{ public int item; }} obj.item=5;	Make field public.	Java
$arr[52]	if ($arr.Count -gt 52) {{ $arr[52] }}	Check bounds.	PowerShell
let a = 'world'	let a = "world"	Double quotes.	Swift
data[2]	if data.indices.contains(2) {{ data[2] }}	Check index.	Swift
if [ $result = 31 ]; then	if [ "$result" = 31 ]; then	Quote variable.	Shell
<user><desc>data</desc><name>16</name></user	<user><desc>data</desc><name>16</name></user>	Add closing >.	XML
class Person {{ int val; }};	class Person {{ public: int val; }};	Make public.	C++
if b > 63 puts 'output'	if b > 63 puts 'output' end	Add 'end'.	Ruby
DELETE FROM orders WHERE age=28	DELETE FROM orders WHERE age=28;	Add semicolon.	SQL
print('message')	print('message')	Correct.	R
List(21,94,2)	List(21,94,2)	Correct.	Scala
var x int	var x int	Correct.	Go
if (count = 55) {{}}	if (count == 55) {{}}	Use ==.	Kotlin
let s1 = String::from("value"); let s2 = s1; println!("{{}}", s1);	let s1 = String::from("value"); let s2 = 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
if (foo) console.log('yes') else console.log('no')	if (foo) console.log('yes'); else console.log('no');	Missing semicolon.	JavaScript
if (val = 100) {}	if (val == 100) {}	Use ==.	Dart
List<int> list = [1,2,3];	List<int> list = [1,2,3];	Correct.	Dart
if (foo = 3) {{}}	if (foo === 3) {{}}	Use === for equality.	JavaScript
'data' + 73	'data' + str(73)	Can't add int to string.	Python
def test puts 'hello' end	def test puts 'hello' end	Correct.	Ruby
<a href='https://demo.net' target='_blank'>	<a href='https://demo.net' target='_blank' rel='noopener'>	Add rel for security.	HTML
const result = 47; result = 17;	let result = 47; result = 17;	Cannot reassign const.	JavaScript
{{'value':47, 'id' 22}}	{{'value':47, 'id':22}}	Colon missing.	Python
{{'value':'result'}}	{{"value":"result"}}	Use double quotes.	JSON
echo 'info'	echo 'info';	Add semicolon.	PHP
let foo = 56; let foo = 7;	let foo = 56; foo = 7;	Duplicate declaration.	JavaScript
int* person = nullptr; *person=5;	int* person = new int; *person=5;	Allocate memory.	C++
[x*x for x in items if x > 30]	[x*x for x in items if x > 30]	Correct list comprehension.	Python
p {{ color: #333 }}	p {{ color: #333; }}	Add semicolon.	CSS
let val: i32 = "hello";	let val: &str = "hello";	Type mismatch.	Rust
$x = 5; echo $x	$x = 5; echo $x;	Missing semicolon.	PHP
let data: number \| null = null; data.toFixed(99);	let data: number \| null = null; if(data!==null) data.toFixed(99);	Null check.	TypeScript
var x = 27;	var x = 27;	Correct.	Dart
[16, 88, 48	[16, 88, 48]	Close bracket.	Python
for foo in range(35) print(foo)	for foo in range(35): print(foo)	Colon after for.	Python
SELECT COUNT(*) FROM users	SELECT COUNT(*) FROM users;	Missing semicolon.	SQL
x = 5; if x > 3, disp('large'), end	x = 5; if x > 3, disp('large'), end	Correct.	MATLAB
let a = 66; a += 1;	let mut a = 66; a += 1;	Need mut to modify.	Rust
lambda x: x+1	lambda x: x+1	Correct lambda.	Python
class = 'output'	class_name = 'output'	'class' is a keyword.	Python
fn baz() -> i32 {{ 77 }}	fn baz() -> i32 {{ 77 }}	Correct.	Rust
// comment	/* comment */	Use /* */.	CSS
var x = 5; x = true	var x = 5; x = 10	Type mismatch.	Kotlin
console.log('value'	console.log('value')	Close parenthesis.	JavaScript
name: info age: 80	name: info age: 80	Correct.	YAML
let b: Int = 'world'	let b: String = 'world'	Fix type.	Swift
if (item = 45)	if (item == 45)	Use ==.	R
<br></br>	<br>	Self-closing.	HTML
num == '50'	num === 50	Use strict equality.	JavaScript
$arr[36]	if ($arr.Count -gt 36) {{ $arr[36] }}	Check bounds.	PowerShell
x := 78	x := 78	Correct.	Go
let item = 'output'	let item = "output"	Double quotes.	Swift
@media screen {{ body {{}} }}	@media screen {{ body {{}} }}	Correct.	CSS
["value", 85]	["value", 85]	Correct.	JSON
.Order {{ color: red; }}	.Order {{ color: red; }}	Correct.	CSS
int items[9]; items[9]=5;	int items[9]; if(9<9){{}} else items[9]=5;	Bounds check.	C++
if item = 90	if item == 90	Use ==.	Go
let val: number = 'value';	let val: string = 'value';	Fix type.	TypeScript
<root><child>text</child></root>	<root><child>text</child></root>	Correct.	XML
int num = 'info';	String num = 'info';	Type mismatch.	Dart
type MyType = string \| number; let x: MyType = true;	type MyType = string \| number; let x: MyType = 'hello';	Type not in union.	TypeScript
if (bar = 6)	if (bar == 6)	Use ==.	C++
data.forEach(function(y) {{ console.log(y); }})	data.forEach((y) => {{ console.log(y); }})	Arrow functions are cleaner.	JavaScript
cin >> item;	int item; cin >> item;	Declare variable.	C++
with open('input.csv') as file_handle: data = file_handle.read()	with open('input.csv') as file_handle: data = file_handle.read()	Correct.	Python
local c = 98	local c = 98	Correct.	Lua
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(71);	const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(71, () => console.log('listening'));	Add callback.	Node.js
var a int = 'test'	var a string = 'test'	Type mismatch.	Go
let v=vec![18,85,15]; let head=&v[0]; v.push(64);	let mut v=vec![18,85,15]; let head=v[0]; v.push(64);	Copy instead of reference.	Rust
'test' + 39	'test' + 39.to_s	Convert int.	Ruby
assert y > 70	assert y > 70	Correct.	Python
String data = 'info';	String data = "info";	Double quotes.	Java
[35, 72, 96	[35, 72, 96]	Close bracket.	Ruby
int &ref;	int x; int &ref = x;	Reference must be initialized.	C++

class Product {{ int temp; }};

class Product {{ public: int temp; }};

Make public.

C++

try: x = 1 / 0 except pass

try: x = 1 / 0 except Exception: pass

Specify exception type.

Python

print('output')

Correct.

R

Add rel for security.

HTML

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

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

Initialize variable.

Java

else print('value')

else: print('value')

Colon after else.

Python

let mut result=41; let ref1=&mut result; let ref2=&mut result;

let mut result=41; {{ let ref1=&mut result; }} let ref2=&mut result;

Only one mutable borrow.

Rust

let text1 = String::from("world"); let text2 = text1; println!("{{}}", text1);

let text1 = String::from("world"); let text2 = text1.clone(); println!("{{}}", text1);

Clone to avoid move.

Rust

var c int = 'test'

var c string = 'test'

Type mismatch.

Go

div {{ color=#333; }}

div {{ color: #333; }}

Use colon.

CSS

fn compute() -> i32 {{ 30 }}

Correct.

Rust

c = 67

c=67

No spaces.

Shell

<hr>

Self-closing.

HTML

class Child Entity:

class Child(Entity):

Inheritance uses parentheses.

Python

Remove trailing comma.

JSON

if foo = 10:

if foo == 10:

Use == for comparison.

Python

Add alt text.

HTML

switch(c){{ case 94: break; }}

switch(c){{ case 94: break; default: break; }}

Add default case.

Java

if result = 52 then print('world') end

if result == 52 then print('world') end

Use ==.

Lua

h1 {{ font-size:86px color:#333; }}

h1 {{ font-size:86px; color:#333; }}

Add semicolon.

CSS

function render(item) print(item) end

Correct.

Lua

<div><p>world</div></p>

<div><p>world</p></div>

Nest properly.

HTML

package main func main() {{}}

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

Import needed.

Go

raise 'hello'

raise Exception('hello')

Raise needs an exception class.

Python

x := 34

Correct.

Go

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

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

Make field public.

Java

$arr[52]

if ($arr.Count -gt 52) {{ $arr[52] }}

Check bounds.

PowerShell

let a = 'world'

let a = "world"

Double quotes.

Swift

data[2]

if data.indices.contains(2) {{ data[2] }}

Check index.

Swift

if [ $result = 31 ]; then

if [ "$result" = 31 ]; then

Quote variable.

Shell

<user><desc>data</desc><name>16</name></user

Add closing >.

XML

class Person {{ int val; }};

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

Make public.

C++

if b > 63 puts 'output'

if b > 63 puts 'output' end

Add 'end'.

Ruby

DELETE FROM orders WHERE age=28

DELETE FROM orders WHERE age=28;

Add semicolon.

SQL

print('message')

Correct.

R

List(21,94,2)

Correct.

Scala

var x int

Correct.

Go

if (count = 55) {{}}

if (count == 55) {{}}

Use ==.

Kotlin

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

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

Clone to avoid move.

Rust

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

Correct.

Shell

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

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

Missing semicolon.

JavaScript

if (val = 100) {}

if (val == 100) {}

Use ==.

Dart

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

Correct.

Dart

if (foo = 3) {{}}

if (foo === 3) {{}}

Use === for equality.

JavaScript

'data' + 73

'data' + str(73)

Can't add int to string.

Python

def test puts 'hello' end

Correct.

Ruby

Add rel for security.

HTML

const result = 47; result = 17;

let result = 47; result = 17;

Cannot reassign const.

JavaScript

Colon missing.

Python

Use double quotes.

JSON

echo 'info'

echo 'info';

Add semicolon.

PHP

let foo = 56; let foo = 7;

let foo = 56; foo = 7;

Duplicate declaration.

JavaScript

int* person = nullptr; *person=5;

int* person = new int; *person=5;

Allocate memory.

C++

[x*x for x in items if x > 30]

Correct list comprehension.

Python

p {{ color: #333 }}

p {{ color: #333; }}

Add semicolon.

CSS

let val: i32 = "hello";

let val: &str = "hello";

Type mismatch.

Rust

$x = 5; echo $x

$x = 5; echo $x;

Missing semicolon.

PHP

let data: number | null = null; data.toFixed(99);

let data: number | null = null; if(data!==null) data.toFixed(99);

Null check.

TypeScript

var x = 27;

Correct.

Dart

[16, 88, 48

[16, 88, 48]

Close bracket.

Python

for foo in range(35) print(foo)

for foo in range(35): print(foo)

Colon after for.

Python

SELECT COUNT(*) FROM users

SELECT COUNT(*) FROM users;

Missing semicolon.

SQL

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

Correct.

MATLAB

let a = 66; a += 1;

let mut a = 66; a += 1;

Need mut to modify.

Rust

lambda x: x+1

Correct lambda.

Python

class = 'output'

class_name = 'output'

'class' is a keyword.

Python

fn baz() -> i32 {{ 77 }}

Correct.

Rust

// comment

/* comment */

Use /* */.

CSS

var x = 5; x = true

var x = 5; x = 10

Type mismatch.

Kotlin

console.log('value'

console.log('value')

Close parenthesis.

JavaScript

name: info age: 80

Correct.

YAML

let b: Int = 'world'

let b: String = 'world'

Fix type.

Swift

if (item = 45)

if (item == 45)

Use ==.

R

<br>

Self-closing.

HTML

num == '50'

num === 50

Use strict equality.

JavaScript

$arr[36]

if ($arr.Count -gt 36) {{ $arr[36] }}

Check bounds.

PowerShell

x := 78

Correct.

Go

let item = 'output'

let item = "output"

Double quotes.

Swift

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

Correct.

CSS

["value", 85]

Correct.

JSON

.Order {{ color: red; }}

Correct.

CSS

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

int items[9]; if(9<9){{}} else items[9]=5;

Bounds check.

C++

if item = 90

if item == 90

Use ==.

Go

let val: number = 'value';

let val: string = 'value';

Fix type.

TypeScript

Correct.

XML

int num = 'info';

String num = 'info';

Type mismatch.

Dart

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

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

Type not in union.

TypeScript

if (bar = 6)

if (bar == 6)

Use ==.

C++

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

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

Arrow functions are cleaner.

JavaScript

cin >> item;

int item; cin >> item;

Declare variable.

C++

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

Correct.

Python

local c = 98

Correct.

Lua

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(71);

const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(71, () => console.log('listening'));

Add callback.

Node.js

var a int = 'test'

var a string = 'test'

Type mismatch.

Go

let v=vec![18,85,15]; let head=&v[0]; v.push(64);

let mut v=vec![18,85,15]; let head=v[0]; v.push(64);

Copy instead of reference.

Rust

'test' + 39

'test' + 39.to_s

Convert int.

Ruby

assert y > 70

Correct.

Python

String data = 'info';

String data = "info";

Double quotes.

Java

[35, 72, 96

[35, 72, 96]

Close bracket.

Ruby

int &ref;

int x; int &ref = x;

Reference must be initialized.

C++