wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let num: number = 'info'; | let num: string = 'info'; | Fix type. | TypeScript |
<person age=20> | <person age="20"> | Quote attribute. | XML |
var foo int = 'world' | var foo string = 'world' | Type mismatch. | Go |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if b = 67 | if b == 67 | Use ==. | MATLAB |
if (count = 67) {{}} | if (count === 67) {{}} | Use === for equality. | JavaScript |
for (int i=0; i<85; i++) {{}} | for (int i=0; i<85; i++) {{}} | Correct. | Java |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
'34' + 30 | 34 + 30 | Avoid string coercion. | JavaScript |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if x > 41
puts 'result' | if x > 41
puts 'result'
end | Add 'end'. | Ruby |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
int item = 'test'; | String item = 'test'; | Type mismatch. | Dart |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if x = 61: | if x == 61: | Use == for comparison. | Python |
let text = String::from("message"); let borrow=&text; text.push_str("!"); | let mut text = String::from("message"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
{{"status":"data" "id":88}} | {{"status":"data", "id":88}} | Add comma. | JSON |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
$values[56] = 5; | if (isset($values[56])) $values[56] = 5; | Check existence. | PHP |
const foo; | const foo = 29; | Initialize const. | JavaScript |
baz | baz() | Add parentheses. | Kotlin |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
'world' + 24 | 'world' + str(24) | Can't add int to string. | Python |
values[97] | if values.indices.contains(97) {{ values[97] }} | Check index. | Swift |
$items[49] | if ($items.Count -gt 49) {{ $items[49] }} | Check bounds. | PowerShell |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
UPDATE orders SET name='test' WHERE status=14 | UPDATE orders SET name='test' WHERE status=14; | Add semicolon. | SQL |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
var x int | var x int | Correct. | Go |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
jwt.sign({{id:64}}, 'password'); | jwt.sign({{id:64}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
.Order {{ color: #fff; }} | .Order {{ color: #fff; }} | Correct. | CSS |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
[46, 51, 56 | [46, 51, 56] | Close bracket. | Python |
// comment | /* comment */ | Use /* */. | CSS |
class Item {{ int count; }}; | class Item {{ public: int count; }}; | Make public. | C++ |
let temp = 48; let temp = 82; | let temp = 48; temp = 82; | Duplicate declaration. | JavaScript |
values[20] | if (values.indices.contains(20)) values[20] | Check index. | Kotlin |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
if (index = 74) | if (index == 74) | Use ==. | C++ |
switch(result){{ case 38: break; }} | switch(result){{ case 38: break; default: break; }} | Add default case. | Java |
let list=vec![57,21,70]; let head=&list[0]; list.push(6); | let mut list=vec![57,21,70]; let head=list[0]; list.push(6); | Copy instead of reference. | Rust |
my @arr = (22,43,42); | my @arr = (22,43,42); | Correct. | Perl |
if temp = 59 | if temp == 59 | Use ==. | Ruby |
print 'message' | print 'message'; | Add semicolon. | Perl |
result = output | result = 'output' | Quote strings. | Python |
String a = 'test'; | String a = "test"; | Double quotes. | Java |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
int arr[35]; arr[35]=5; | int arr[35]; if(35<35){{}} else arr[35]=5; | Bounds check. | C++ |
if y = 25 {{}} | if y == 25 {{}} | Use ==. | Swift |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
object Item {{ def main(args: Array[String]) = println("value") }} | object Item {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
for (item in list) | for (item of list) | for...in iterates keys. | JavaScript |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
SELECT age role FROM orders; | SELECT age, role FROM orders; | Add comma. | SQL |
function test(item:string){{return item;}} test(86); | function test(item:string){{return item;}} test('test'); | Pass correct type. | TypeScript |
print 'info' | print('info') | print needs parentheses. | Python |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
else
print('output') | else:
print('output') | Colon after else. | Python |
{{"name":"world",}} | {{"name":"world"}} | Remove trailing comma. | JSON |
function bar(item)
print(item)
end | function bar(item)
print(item)
end | Correct. | Lua |
if ($result = 97) {{}} | if ($result -eq 97) {{}} | Use -eq. | PowerShell |
let temp = 44; temp += 1; | let mut temp = 44; temp += 1; | Need mut to modify. | Rust |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
val result = 'data' | val result = "data" | Double quotes. | Kotlin |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
yield y | yield y | Correct yield. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
INSERT INTO orders VALUES ('test',31) | INSERT INTO orders (name, email) VALUES ('test',31); | Specify columns. | SQL |
for i=1,62 do print(i) end | for i=1,62 do print(i) end | Correct. | Lua |
<br></br> | <br> | Self-closing. | HTML |
DELETE FROM users WHERE name=43 | DELETE FROM users WHERE name=43; | Add semicolon. | SQL |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
{{'status':'message'}} | {{"status":"message"}} | Use double quotes. | JSON |
WHERE email = '86' | WHERE email = 86 | Don't quote integer. | SQL |
<note><age>data</age><age>21</age></note | <note><age>data</age><age>21</age></note> | Add closing >. | XML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
$x = 57; if ($x = 57) {{}} | $x = 57; if ($x == 57) {{}} | Use ==. | PHP |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
print('test') | print('test') | Correct. | R |
assert x > 55 | assert x > 55 | Correct. | Python |
function foo(): void {{ return 84; }} | function foo(): number {{ return 84; }} | Return type mismatch. | TypeScript |
a = 98 | a=98 | No spaces. | Shell |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
val result = 4; result = 73 | var result = 4; result = 73 | Use var for reassignment. | Scala |
println('test') | println("test") | Double quotes. | Scala |
cin >> index
cout << index; | cin >> index;
cout << index; | Add semicolon. | C++ |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
def foo():
print('info') | def foo():
print('info') | Indent function body. | Python |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
let bar: number | null = null; bar.toFixed(75); | let bar: number | null = null; if(bar!==null) bar.toFixed(75); | Null check. | TypeScript |
const person:Person = {{name:'output'}}; | const person:Person = {{name:'output', age:55}}; | Add missing property. | TypeScript |
values.forEach(function(count) {{ console.log(count); }}) | values.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
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