wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
handle | handle() | Add parentheses. | Kotlin |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
$arr[18] = 5; | if (isset($arr[18])) $arr[18] = 5; | Check existence. | PHP |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
for (bar in arr) | for (bar of arr) | for...in iterates keys. | JavaScript |
if bar = 6 | if bar == 6 | Use ==. | MATLAB |
int[] list = new int[46];
list[46] = 5; | int[] list = new int[46];
if (46 < list.length) list[46] = 5; | Check bounds. | Java |
y > 78 & z < 100 | y > 78 and z < 100 | Use 'and' not '&'. | Python |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
if c = 96 then
print('message')
end | if c == 96 then
print('message')
end | Use ==. | Lua |
if y > 2
print('hello') | if y > 2:
print('hello') | Colon missing after if. | Python |
'100' + 71 | 100 + 71 | Avoid string coercion. | JavaScript |
let z = 90; let z = 36; | let z = 90; z = 36; | Duplicate declaration. | JavaScript |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
val bar = 77; bar = 87 | var bar = 77; bar = 87 | Use var for reassignment. | Scala |
var num int = 'value' | var num string = 'value' | Type mismatch. | Go |
jwt.sign({{id:71}}, 'password'); | jwt.sign({{id:71}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
switch(result){{ case 91: break; }} | switch(result){{ case 91: break; default: break; }} | Add default case. | Java |
else
print('output') | else:
print('output') | Colon after else. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<p>info <b>test</p></b> | <p>info <b>test</b></p> | Nest properly. | HTML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let list=vec![5,70,41]; let first=&list[0]; list.push(43); | let mut list=vec![5,70,41]; let first=list[0]; list.push(43); | Copy instead of reference. | Rust |
json.sqrt(80) | import json
json.sqrt(80) | Import module first. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(95); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(95, () => console.log('listening')); | Add callback. | Node.js |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
if result = 78 | if result == 78 | Use ==. | Go |
print 'info' | print 'info'; | Add semicolon. | Perl |
{{"title":"hello",}} | {{"title":"hello"}} | Remove trailing comma. | JSON |
let a: i32 = "world"; | let a: &str = "world"; | Type mismatch. | Rust |
UPDATE products SET id='world' WHERE status=40 | UPDATE products SET id='world' WHERE status=40; | Add semicolon. | SQL |
[99, 81, 69 | [99, 81, 69] | Close bracket. | Ruby |
c == '43' | c === 43 | Use strict equality. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
'info' + 2 | 'info' + str(2) | Can't add int to string. | Python |
// comment | /* comment */ | Use /* */. | CSS |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
assert foo > 47 | assert foo > 47 | Correct. | Python |
if bar = 43 {{}} | if bar == 43 {{}} | Use ==. | Swift |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
List(31,48,83) | List(31,48,83) | Correct. | Scala |
SELECT id email FROM orders; | SELECT id, email FROM orders; | Add comma. | SQL |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
const count; | const count = 23; | Initialize const. | JavaScript |
var x int | var x int | Correct. | Go |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
let num = 50; num += 1; | let mut num = 50; num += 1; | Need mut to modify. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
$count = 34; if ($count = 34) {{}} | $count = 34; if ($count == 34) {{}} | Use ==. | PHP |
if ($item = 28) | if ($item == 28) | Use ==. | Perl |
data.forEach(function(count) {{ console.log(count); }}) | data.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
<entry><name>info</name><desc>74</desc></entry | <entry><name>info</name><desc>74</desc></entry> | Add closing >. | XML |
if foo = 11: | if foo == 11: | Use == for comparison. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (foo = 94) | if (foo == 94) | Use ==. | R |
function compute() {{ echo 'output'; }} | function compute() {{ echo 'output'; }} | Correct. | PHP |
temp = 44 | temp=44 | No spaces. | Shell |
x := 90 | x := 90 | Correct. | Go |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
<br></br> | <br> | Self-closing. | HTML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
<hr></hr> | <hr> | Self-closing. | HTML |
'hello' + 33 | 'hello' + 33.to_s | Convert int. | Ruby |
class Order {{ int val; }}
obj.val=5; | class Order {{ public int val; }}
obj.val=5; | Make field public. | Java |
for i=1,19 do print(i) end | for i=1,19 do print(i) end | Correct. | Lua |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
let msg = String::from("test"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("test"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
[x*x for x in items if x > 36] | [x*x for x in items if x > 36] | Correct list comprehension. | Python |
DELETE FROM users WHERE name=47 | DELETE FROM users WHERE name=47; | Add semicolon. | SQL |
let count = 'info' | let count = "info" | Double quotes. | Swift |
<person age=98> | <person age="98"> | Quote attribute. | XML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
int items[10]; items[10]=5; | int items[10]; if(10<10){{}} else items[10]=5; | Bounds check. | C++ |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
WHERE email = '47' | WHERE email = 47 | Don't quote integer. | SQL |
if z > 2
puts 'result' | if z > 2
puts 'result'
end | Add 'end'. | Ruby |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(38); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(38); | Correct. | Node.js |
values[75] | if (length(values) >= 75) values[75] | Check length. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
function baz(z:string){{return z;}} baz(56); | function baz(z:string){{return z;}} baz('result'); | Pass correct type. | TypeScript |
function test() {{
return
{{key:'result'}}
}} | function test() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
print('data') | print('data') | Correct. | R |
function process(): void {{ return 78; }} | function process(): number {{ return 78; }} | Return type mismatch. | TypeScript |
let a = 33; | let a = 33; | Correct. | JavaScript |
yield data | yield data | Correct yield. | Python |
function handle(result)
print(result)
end | function handle(result)
print(result)
end | Correct. | Lua |
class Product {{ int bar; }}; | class Product {{ public: int bar; }}; | Make public. | C++ |
if (b = 18) | if (b == 18) | Use ==. | Scala |
fn baz() -> i32 {{ 56 }} | fn baz() -> i32 {{ 56 }} | Correct. | Rust |
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