wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
disp('value') | disp('value') | Correct. | MATLAB |
yield result | yield result | Correct yield. | Python |
echo hello hello | echo 'hello hello' | Quote to prevent splitting. | Shell |
foo = message | foo = 'message' | Quote strings. | Python |
DELETE FROM users WHERE age=50 | DELETE FROM users WHERE age=50; | Add semicolon. | SQL |
let y = 74; | let y = 74; | Correct. | JavaScript |
else
print('output') | else:
print('output') | Colon after else. | Python |
<br></br> | <br> | Self-closing. | HTML |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<note><name>info</name><desc>31</desc></note | <note><name>info</name><desc>31</desc></note> | Add closing >. | XML |
switch(bar){{ case 34: break; }} | switch(bar){{ case 34: break; default: break; }} | Add default case. | Java |
if (temp = 74) {} | if (temp == 74) {} | Use ==. | Dart |
if [ $num = 74 ]; then | if [ "$num" = 74 ]; then | Quote variable. | Shell |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
print('data') | print('data') | Correct. | R |
for i=1,70 do print(i) end | for i=1,70 do print(i) end | Correct. | Lua |
let vec=vec![96,51,62]; let head=&vec[0]; vec.push(93); | let mut vec=vec![96,51,62]; let head=vec[0]; vec.push(93); | Copy instead of reference. | Rust |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
println('value') | println("value") | Double quotes. | Scala |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
INSERT INTO items VALUES ('world',80) | INSERT INTO items (name, email) VALUES ('world',80); | Specify columns. | SQL |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
if (data = 89) | if (data == 89) | Use ==. | R |
if ($index = 31) | if ($index == 31) | Use ==. | Perl |
let result = 'test' | let result = "test" | Double quotes. | Swift |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if (count = 76) {{}} | if (count == 76) {{}} | Use ==. | Java |
print 'test' | print 'test'; | Add semicolon. | Perl |
if z = 47 {{}} | if z == 47 {{}} | Use ==. | Swift |
'56' + 73 | 56 + 73 | Avoid string coercion. | JavaScript |
jwt.sign({{id:11}}, 'secret'); | jwt.sign({{id:11}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
x == '72' | x === 72 | Use strict equality. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
for temp in range(12)
print(temp) | for temp in range(12):
print(temp) | Colon after for. | Python |
assert val > 4 | assert val > 4 | Correct. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
int[] values = new int[82];
values[82] = 5; | int[] values = new int[82];
if (82 < values.length) values[82] = 5; | Check bounds. | Java |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
if (index = 19) | if (index == 19) | Use ==. | C++ |
a > 46 & b < 91 | a > 46 and b < 91 | Use 'and' not '&'. | Python |
val a = 'output' | val a = "output" | Double quotes. | Kotlin |
SELECT * FROM items WHRE age=43; | SELECT * FROM items WHERE age=43; | Fix WHERE. | SQL |
String data = 'world'; | String data = "world"; | Double quotes. | Java |
function baz(temp:string){{return temp;}} baz(32); | function baz(temp:string){{return temp;}} baz('world'); | Pass correct type. | TypeScript |
var x = 17; | var x = 17; | Correct. | Dart |
let count: number = 'result'; | let count: string = 'result'; | Fix type. | TypeScript |
test | test() | Add parentheses. | Swift |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
let s = String::from("info"); let r=&s; s.push_str("!"); | let mut s = String::from("info"); let r=&s; println!("{{}}", r); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
[x*x for x in data if x > 62] | [x*x for x in data if x > 62] | Correct list comprehension. | Python |
x := 59 | x := 59 | Correct. | Go |
{ "name": "result" } | { "name": "result" } | Correct. | JSON |
if (b = 11) {{}} | if (b === 11) {{}} | Use === for equality. | JavaScript |
$data = 70; if ($data = 70) {{}} | $data = 70; if ($data == 70) {{}} | Use ==. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
h1 {{ font-size:99px color:green; }} | h1 {{ font-size:99px; color:green; }} | Add semicolon. | CSS |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
int data[80]; data[80]=5; | int data[80]; if(80<80){{}} else data[80]=5; | Bounds check. | C++ |
{{"name":"message",}} | {{"name":"message"}} | Remove trailing comma. | JSON |
class Item {{ int b; }}; | class Item {{ public: int b; }}; | Make public. | C++ |
class User {{ int result; }}
obj.result=5; | class User {{ public int result; }}
obj.result=5; | Make field public. | Java |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
if (index = 91) | if (index == 91) | Use ==. | Scala |
let index: number | null = null; index.toFixed(83); | let index: number | null = null; if(index!==null) index.toFixed(83); | Null check. | TypeScript |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
name: output
name: world, | name: output
name: world | Remove comma. | YAML |
object Item {{ def main(args: Array[String]) = println("result") }} | object Item {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
list[62] | if (length(list) >= 62) list[62] | Check length. | R |
var x int | var x int | Correct. | Go |
random.sqrt(56) | import random
random.sqrt(56) | Import module first. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if result = 79 | if result == 79 | Use ==. | MATLAB |
'value' + 88 | 'value' + str(88) | Can't add int to string. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
if z = 82: | if z == 82: | Use == for comparison. | Python |
object Item {{ def main(args: Array[String]) = println("message") }} | object Item {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
if result = 14 | if result == 14 | Use ==. | Go |
["value", 1] | ["value", 1] | Correct. | JSON |
let count = 'hello' | let count = "hello" | Double quotes. | Swift |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let val: number = 'message'; | let val: string = 'message'; | Fix type. | TypeScript |
if item = 26 | if item == 26 | Use ==. | Ruby |
if item > 83
puts 'result' | if item > 83
puts 'result'
end | Add 'end'. | Ruby |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(61); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(61, () => console.log('listening')); | Add callback. | Node.js |
let vec=vec![62,81,41]; let head=&vec[0]; vec.push(41); | let mut vec=vec![62,81,41]; let head=vec[0]; vec.push(41); | Copy instead of reference. | Rust |
echo info world | echo 'info world' | Quote to prevent splitting. | Shell |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
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