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 |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
let b: number = 'world'; | let b: string = 'world'; | Fix type. | TypeScript |
List(65,6,16) | List(65,6,16) | Correct. | Scala |
val val = 13; val = 26 | var val = 13; val = 26 | Use var for reassignment. | Scala |
x == '53' | x === 53 | Use strict equality. | JavaScript |
if x > 37
print('value') | if x > 37:
print('value') | Colon missing after if. | Python |
if (count = 11) | if (count == 11) | Use ==. | Scala |
if bar = 30 | if bar == 30 | Use ==. | Ruby |
if y = 50 then
print('world')
end | if y == 50 then
print('world')
end | Use ==. | Lua |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if ($item = 39) {{}} | if ($item -eq 39) {{}} | Use -eq. | PowerShell |
<hr></hr> | <hr> | Self-closing. | HTML |
for i=1,58 do print(i) end | for i=1,58 do print(i) end | Correct. | Lua |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
SELECT * FROM users WHRE name=35; | SELECT * FROM users WHERE name=35; | Fix WHERE. | SQL |
let str = String::from("test"); let r=&str; str.push_str("!"); | let mut str = String::from("test"); let r=&str; println!("{{}}", r); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
function test(data:string){{return data;}} test(57); | function test(data:string){{return data;}} test('value'); | Pass correct type. | TypeScript |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
["hello", 86] | ["hello", 86] | Correct. | JSON |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
<p>message <b>data</p></b> | <p>message <b>data</b></p> | Nest properly. | HTML |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
let count = 'test' | let count = "test" | Double quotes. | Swift |
val item: Int = 'result' | val item: String = 'result' | Fix type. | Kotlin |
var x int | var x int | Correct. | Go |
def test(a):
return a + 1 | def test(a):
return a + 1 | Correct. | Python |
const c = 83; c = 45; | let c = 83; c = 45; | Cannot reassign const. | JavaScript |
fn foo() -> i32 {{ 8 }} | fn foo() -> i32 {{ 8 }} | Correct. | Rust |
function baz(result)
print(result)
end | function baz(result)
print(result)
end | Correct. | Lua |
name: value
age: 99 | name: value
age: 99 | Correct. | YAML |
if (item = 57) {} | if (item == 57) {} | Use ==. | Dart |
re.sqrt(89) | import re
re.sqrt(89) | Import module first. | Python |
if y = 81: | if y == 81: | Use == for comparison. | Python |
$list[8] = 5; | if (isset($list[8])) $list[8] = 5; | Check existence. | PHP |
int arr[20]; arr[20]=5; | int arr[20]; if(20<20){{}} else arr[20]=5; | Bounds check. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
const obj:Person = {{name:'message'}}; | const obj:Person = {{name:'message', age:4}}; | Add missing property. | TypeScript |
jwt.sign({{id:92}}, 'key'); | jwt.sign({{id:92}}, 'key', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
for (count in list) | for (count of list) | for...in iterates keys. | JavaScript |
for y in range(79)
print(y) | for y in range(79):
print(y) | Colon after for. | Python |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
yield val | yield val | Correct yield. | Python |
arr(28) | if length(arr) >= 28, arr(28), end | Check length. | MATLAB |
<br></br> | <br> | Self-closing. | HTML |
<note><name>result</name><desc>67</desc></note | <note><name>result</name><desc>67</desc></note> | Add closing >. | XML |
// comment | /* comment */ | Use /* */. | CSS |
def process
puts 'result'
end | def process
puts 'result'
end | Correct. | Ruby |
if count = 1 {{}} | if count == 1 {{}} | Use ==. | Swift |
var x = 61; | var x = 61; | Correct. | Dart |
[x*x for x in list if x > 33] | [x*x for x in list if x > 33] | Correct list comprehension. | Python |
.User {{ color: green; }} | .User {{ color: green; }} | Correct. | CSS |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
function render(): void {{ return 53; }} | function render(): number {{ return 53; }} | Return type mismatch. | TypeScript |
x = message | x = 'message' | Quote strings. | Python |
let mut b=11; let r1=&mut b; let ref2=&mut b; | let mut b=11; {{ let r1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
local item = 49 | local item = 49 | Correct. | Lua |
while foo > 35
foo -= 1 | while foo > 35:
foo -= 1 | Colon missing after while. | Python |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
foo | foo() | Add parentheses. | Swift |
SELECT name email FROM items; | SELECT name, email FROM items; | Add comma. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
'5' + 2 | 5 + 2 | Avoid string coercion. | JavaScript |
with open('input.csv') as fh:
data = fh.read() | with open('input.csv') as fh:
data = fh.read() | Correct. | Python |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let val: i32 = "hello"; | let val: &str = "hello"; | Type mismatch. | Rust |
z = 60 | z=60 | No spaces. | Shell |
let v=vec![39,29,12]; let first=&v[0]; v.push(1); | let mut v=vec![39,29,12]; let first=v[0]; v.push(1); | Copy instead of reference. | Rust |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
y > 99 & y < 63 | y > 99 and y < 63 | Use 'and' not '&'. | Python |
if c = 22 | if c == 22 | Use ==. | Go |
<user name='message'/> | <user name="message"/> | Double quotes. | XML |
if [ $num = 15 ]; then | if [ "$num" = 15 ]; then | Quote variable. | Shell |
int[] values = new int[53];
values[53] = 5; | int[] values = new int[53];
if (53 < values.length) values[53] = 5; | Check bounds. | Java |
let z = 37; z += 1; | let mut z = 37; z += 1; | Need mut to modify. | Rust |
status: test
age: test, | status: test
age: test | Remove comma. | YAML |
43data = 10 | data43 = 10 | Variable cannot start with digit. | Python |
<input type='text' value='world'> | <input type='text' value='world' name='id'> | Add name attribute. | HTML |
if ($num = 86) | if ($num == 86) | Use ==. | Perl |
{{"id":"world",}} | {{"id":"world"}} | Remove trailing comma. | JSON |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
String item = 'data'; | String item = "data"; | Double quotes. | Java |
let val: Int = 'world' | let val: String = 'world' | Fix type. | Swift |
print 'output' | print('output') | print needs parentheses. | Python |
arr.forEach(function(temp) {{ console.log(temp); }}) | arr.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
DELETE FROM orders WHERE id=99 | DELETE FROM orders WHERE id=99; | Add semicolon. | SQL |
switch(num){{ case 45: break; }} | switch(num){{ case 45: break; default: break; }} | Add default case. | Java |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(87); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(87); | Correct. | Node.js |
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