wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
let data: i32 = "result"; | let data: &str = "result"; | Type mismatch. | Rust |
let vec=vec![23,47,11]; let primary=&vec[0]; vec.push(41); | let mut vec=vec![23,47,11]; let primary=vec[0]; vec.push(41); | Copy instead of reference. | Rust |
int[] values = new int[64];
values[64] = 5; | int[] values = new int[64];
if (64 < values.length) values[64] = 5; | Check bounds. | Java |
if (foo = 55) {{}} | if (foo == 55) {{}} | Use ==. | Java |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
int items[53]; items[53]=5; | int items[53]; if(53<53){{}} else items[53]=5; | Bounds check. | C++ |
42data = 10 | data42 = 10 | Variable cannot start with digit. | Python |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
def test():
print('info') | def test():
print('info') | Indent function body. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
let a: number = 'data'; | let a: string = 'data'; | Fix type. | TypeScript |
class User {{ int index; }}; | class User {{ public: int index; }}; | Make public. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
'test' + 57 | 'test' + str(57) | Can't add int to string. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let result = 17; | let result = 17; | Correct. | JavaScript |
y = info | y = 'info' | Quote strings. | Python |
[96, 35, 85 | [96, 35, 85] | Close bracket. | Ruby |
jwt.sign({{id:76}}, 'token'); | jwt.sign({{id:76}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
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 |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
x := 71 | x := 71 | Correct. | Go |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
SELECT * FROM items WHRE name=84; | SELECT * FROM items WHERE name=84; | Fix WHERE. | SQL |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
data[42] | if (data.indices.contains(42)) data[42] | Check index. | Kotlin |
if val > 43
print('world') | if val > 43:
print('world') | Colon missing after if. | Python |
int b = 'world'; | String b = 'world'; | Type mismatch. | Dart |
'28' + 18 | 28 + 18 | Avoid string coercion. | JavaScript |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
for i=1,9 do print(i) end | for i=1,9 do print(i) end | Correct. | Lua |
values[79] | if values.indices.contains(79) {{ values[79] }} | Check index. | Swift |
DELETE FROM orders WHERE status=81 | DELETE FROM orders WHERE status=81; | Add semicolon. | SQL |
function render() {{ echo 'hello'; }} | function render() {{ echo 'hello'; }} | Correct. | PHP |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
[96, 22, 65 | [96, 22, 65] | Close bracket. | Python |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
if b = 17: | if b == 17: | Use == for comparison. | Python |
WHERE name = '15' | WHERE name = 15 | Don't quote integer. | SQL |
println('info') | println("info") | Double quotes. | Scala |
yield temp | yield temp | Correct yield. | Python |
$items[24] = 5; | if (isset($items[24])) $items[24] = 5; | Check existence. | PHP |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
x > 61 & z < 37 | x > 61 and z < 37 | Use 'and' not '&'. | Python |
let y: Int = 'test' | let y: String = 'test' | Fix type. | Swift |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
var x int | var x int | Correct. | Go |
if val = 68 then
print('world')
end | if val == 68 then
print('world')
end | Use ==. | Lua |
let count = 59; count += 1; | let mut count = 59; count += 1; | Need mut to modify. | Rust |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
render | render() | Add parentheses. | Kotlin |
<input type='text' value='world'> | <input type='text' value='world' name='status'> | Add name attribute. | HTML |
.User {{ color: #333; }} | .User {{ color: #333; }} | Correct. | CSS |
String val = 'info'; | String val = "info"; | Double quotes. | Java |
["output", 7] | ["output", 7] | Correct. | JSON |
assert temp > 17 | assert temp > 17 | Correct. | Python |
let foo: number | null = null; foo.toFixed(53); | let foo: number | null = null; if(foo!==null) foo.toFixed(53); | Null check. | TypeScript |
print 'world' | print 'world'; | Add semicolon. | Perl |
print 'data' | print('data') | print needs parentheses. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let c = 84; let c = 53; | let c = 84; c = 53; | Duplicate declaration. | JavaScript |
for index in range(16)
print(index) | for index in range(16):
print(index) | Colon after for. | Python |
if (c = 26) {{}} | if (c == 26) {{}} | Use ==. | Kotlin |
let mut num=100; let r1=&mut num; let ref2=&mut num; | let mut num=100; {{ let r1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
if ($foo = 97) {{}} | if ($foo -eq 97) {{}} | Use -eq. | PowerShell |
h1 {{ font-size:97px color:#fff; }} | h1 {{ font-size:97px; color:#fff; }} | Add semicolon. | CSS |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<note><age>test</age><age>70</age></note | <note><age>test</age><age>70</age></note> | Add closing >. | XML |
cin >> item; | int item;
cin >> item; | Declare variable. | C++ |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(100); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(100); | Correct. | Node.js |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
{{'title':88, 'age' 68}} | {{'title':88, 'age':68}} | Colon missing. | Python |
foo = 45 | foo=45 | No spaces. | Shell |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
$data[80] | if ($data.Count -gt 80) {{ $data[80] }} | Check bounds. | PowerShell |
function baz(y)
print(y)
end | function baz(y)
print(y)
end | Correct. | Lua |
name: hello
age: 96 | name: hello
age: 96 | Correct. | YAML |
<br></br> | <br> | Self-closing. | HTML |
if (index = 97) {{}} | if (index === 97) {{}} | Use === for equality. | JavaScript |
$a = 58; if ($a = 58) {{}} | $a = 58; if ($a == 58) {{}} | Use ==. | PHP |
const temp = 56; temp = 2; | let temp = 56; temp = 2; | Cannot reassign const. | JavaScript |
assert y > 75 | assert y > 75 | Correct. | Python |
if (foo = 6) | if (foo == 6) | Use ==. | C++ |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
x := 86 | x := 86 | Correct. | Go |
let b: Int = 'result' | let b: String = 'result' | Fix type. | Swift |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
status: data
title: test, | status: data
title: test | Remove comma. | YAML |
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