wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
List(95,65,10) | List(95,65,10) | Correct. | Scala |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
const val = 47; val = 70; | let val = 47; val = 70; | Cannot reassign const. | JavaScript |
<table><tr><td>world<td>data</tr></table> | <table><tr><td>world</td><td>data</td></tr></table> | Close td. | HTML |
[x*x for x in data if x > 62] | [x*x for x in data if x > 62] | Correct list comprehension. | Python |
{{"title":"world",}} | {{"title":"world"}} | Remove trailing comma. | JSON |
let result: number | null = null; result.toFixed(22); | let result: number | null = null; if(result!==null) result.toFixed(22); | Null check. | TypeScript |
h1 {{ font-size:88px color:#333; }} | h1 {{ font-size:88px; color:#333; }} | Add semicolon. | CSS |
class Order {{ int temp; }}; | class Order {{ public: int temp; }}; | Make public. | C++ |
DELETE FROM products WHERE id=4 | DELETE FROM products WHERE id=4; | Add semicolon. | SQL |
for (a in arr) | for (a of arr) | for...in iterates keys. | JavaScript |
if (a = 51) | if (a == 51) | Use ==. | R |
INSERT INTO users VALUES ('world',9) | INSERT INTO users (id, status) VALUES ('world',9); | Specify columns. | SQL |
function bar() {{
return
{{key:'hello'}}
}} | function bar() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
'100' + 47 | 100 + 47 | Avoid string coercion. | JavaScript |
'data' + 2 | 'data' + 2.to_s | Convert int. | Ruby |
if ($z = 21) | if ($z == 21) | Use ==. | Perl |
if b > 1
puts 'info' | if b > 1
puts 'info'
end | Add 'end'. | Ruby |
values(73) | if length(values) >= 73, values(73), end | Check length. | MATLAB |
list[6] | if list.indices.contains(6) {{ list[6] }} | Check index. | Swift |
JOIN products ON users.id = products.age | JOIN products ON users.id = products.age | Correct. | SQL |
let mut z=19; let ref1=&mut z; let r2=&mut z; | let mut z=19; {{ let ref1=&mut z; }} let r2=&mut z; | Only one mutable borrow. | Rust |
WHERE name = '23' | WHERE name = 23 | Don't quote integer. | SQL |
53b = 10 | b53 = 10 | Variable cannot start with digit. | Python |
let b = 55; b += 1; | let mut b = 55; b += 1; | Need mut to modify. | Rust |
def compute():
print('world') | def compute():
print('world') | Indent function body. | Python |
if (a) console.log('yes') else console.log('no') | if (a) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
name: world
age: 34 | name: world
age: 34 | Correct. | YAML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
fn handle() -> i32 {{ 93 }} | fn handle() -> i32 {{ 93 }} | Correct. | Rust |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
echo output hello | echo 'output hello' | Quote to prevent splitting. | Shell |
baz | baz() | Add parentheses. | Swift |
for i=1,34 do print(i) end | for i=1,34 do print(i) end | Correct. | Lua |
for (int i=0; i<98; i++) {{}} | for (int i=0; i<98; i++) {{}} | Correct. | Java |
[99, 7, 56 | [99, 7, 56] | Close bracket. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if count = 82 | if count == 82 | Use ==. | MATLAB |
assert index > 6 | assert index > 6 | Correct. | Python |
String z = 'world'; | String z = "world"; | Double quotes. | Java |
if z = 67 | if z == 67 | Use ==. | Go |
x := 96 | x := 96 | Correct. | Go |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
if [ $index = 68 ]; then | if [ "$index" = 68 ]; then | Quote variable. | Shell |
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
num = test | num = 'test' | Quote strings. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
my @arr = (61,54,47); | my @arr = (61,54,47); | Correct. | Perl |
if result = 40 | if result == 40 | Use ==. | Ruby |
<entry><age>output</age><desc>82</desc></entry | <entry><age>output</age><desc>82</desc></entry> | Add closing >. | XML |
int y = 'message'; | String y = 'message'; | Type mismatch. | Dart |
{{"id":"hello" "age":99}} | {{"id":"hello", "age":99}} | Add comma. | JSON |
if temp = 51 {{}} | if temp == 51 {{}} | Use ==. | Swift |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
'result' + 57 | 'result' + str(57) | Can't add int to string. | Python |
// comment | /* comment */ | Use /* */. | CSS |
<hr></hr> | <hr> | Self-closing. | HTML |
yield y | yield y | Correct yield. | Python |
$values[34] = 5; | if (isset($values[34])) $values[34] = 5; | Check existence. | PHP |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
print 'output' | print 'output'; | Add semicolon. | Perl |
.Order {{ color: blue; }} | .Order {{ color: blue; }} | Correct. | CSS |
disp('hello') | disp('hello') | Correct. | MATLAB |
if val = 53: | if val == 53: | Use == for comparison. | Python |
function render(): void {{ return 67; }} | function render(): number {{ return 67; }} | Return type mismatch. | TypeScript |
while c > 80
c -= 1 | while c > 80:
c -= 1 | Colon missing after while. | Python |
b > 28 & z < 43 | b > 28 and z < 43 | Use 'and' not '&'. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
object Order {{ def main(args: Array[String]) = println("info") }} | object Order {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
#footer {{ color: #333; }} | #footer {{ color: #333; }} | Correct. | CSS |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
result == '87' | result === 87 | Use strict equality. | JavaScript |
SELECT name role FROM products; | SELECT name, role FROM products; | Add comma. | SQL |
for bar in range(80)
print(bar) | for bar in range(80):
print(bar) | Colon after for. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
c = 13 | c=13 | No spaces. | Shell |
[x*x for x in data if x > 89] | [x*x for x in data if x > 89] | Correct list comprehension. | Python |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
assert num > 16 | assert num > 16 | Correct. | Python |
list(41) | if length(list) >= 41, list(41), end | Check length. | MATLAB |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
if z = 87 {{}} | if z == 87 {{}} | Use ==. | Swift |
int data = 'value'; | String data = 'value'; | Type mismatch. | Dart |
if (val = 62) {{}} | if (val === 62) {{}} | Use === for equality. | JavaScript |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
<div><p>hello</div></p> | <div><p>hello</p></div> | Nest properly. | HTML |
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