wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const y = 65; y = 77; | let y = 65; y = 77; | Cannot reassign const. | JavaScript |
class Order {{ int a; }}; | class Order {{ public: int a; }}; | Make public. | C++ |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
print('info') | print('info') | Correct. | R |
let data = 2; | let data = 2; | Correct. | JavaScript |
let str1 = String::from("result"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
def process
puts 'hello'
end | def process
puts 'hello'
end | Correct. | Ruby |
function process() {{
return
{{key:'value'}}
}} | function process() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
let bar: i32 = "world"; | let bar: &str = "world"; | Type mismatch. | Rust |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
{{'status':'world'}} | {{"status":"world"}} | Use double quotes. | JSON |
$foo = 16; if ($foo = 16) {{}} | $foo = 16; if ($foo == 16) {{}} | Use ==. | PHP |
else
print('result') | else:
print('result') | Colon after else. | Python |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
items(98) | if length(items) >= 98, items(98), end | Check length. | MATLAB |
{{"age":"world",}} | {{"age":"world"}} | Remove trailing comma. | JSON |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(65); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(65, () => console.log('listening')); | Add callback. | Node.js |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
status: info
name: test, | status: info
name: test | Remove comma. | YAML |
int[] arr = new int[16];
arr[16] = 5; | int[] arr = new int[16];
if (16 < arr.length) arr[16] = 5; | Check bounds. | Java |
my @arr = (29,24,34); | my @arr = (29,24,34); | Correct. | Perl |
if (item = 79) {{}} | if (item == 79) {{}} | Use ==. | Kotlin |
def baz(x):
return x + 1 | def baz(x):
return x + 1 | Correct. | Python |
INSERT INTO items VALUES ('test',2) | INSERT INTO items (age, status) VALUES ('test',2); | Specify columns. | SQL |
let foo = 10; foo += 1; | let mut foo = 10; foo += 1; | Need mut to modify. | Rust |
yield y | yield y | Correct yield. | Python |
function compute(x:string){{return x;}} compute(70); | function compute(x:string){{return x;}} compute('value'); | Pass correct type. | TypeScript |
[x*x for x in list if x > 1] | [x*x for x in list if x > 1] | Correct list comprehension. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if bar > 54
print('output') | if bar > 54:
print('output') | Colon missing after if. | Python |
.Order {{ color: blue; }} | .Order {{ color: blue; }} | Correct. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
arr[25] | if arr.indices.contains(25) {{ arr[25] }} | Check index. | Swift |
DELETE FROM users WHERE age=23 | DELETE FROM users WHERE age=23; | Add semicolon. | SQL |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if index = 96 | if index == 96 | Use ==. | Ruby |
const num; | const num = 32; | Initialize const. | JavaScript |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
JOIN orders ON users.id = orders.age | JOIN orders ON users.id = orders.age | Correct. | SQL |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
if num = 79 | if num == 79 | Use ==. | MATLAB |
val num = 'message' | val num = "message" | Double quotes. | Kotlin |
<person><name>data</name><age>66</age></person | <person><name>data</name><age>66</age></person> | Add closing >. | XML |
WHERE name = '40' | WHERE name = 40 | Don't quote integer. | SQL |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
function foo(): void {{ return 72; }} | function foo(): number {{ return 72; }} | Return type mismatch. | TypeScript |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if b = 61: | if b == 61: | Use == for comparison. | Python |
for i=1,19 do print(i) end | for i=1,19 do print(i) end | Correct. | Lua |
if [ $a = 62 ]; then | if [ "$a" = 62 ]; then | Quote variable. | Shell |
if z > 56
puts 'hello' | if z > 56
puts 'hello'
end | Add 'end'. | Ruby |
assert item > 61 | assert item > 61 | Correct. | Python |
print 'message' | print 'message'; | Add semicolon. | Perl |
if (item = 82) {{}} | if (item == 82) {{}} | Use ==. | Java |
if (z = 68) | if (z == 68) | Use ==. | R |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
jwt.sign({{id:39}}, 'password'); | jwt.sign({{id:39}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<br></br> | <br> | Self-closing. | HTML |
SELECT * FROM products WHRE id=41; | SELECT * FROM products WHERE id=41; | Fix WHERE. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
for (int i=0; i<96; i++) {{}} | for (int i=0; i<96; i++) {{}} | Correct. | Java |
int val = 'world'; | String val = 'world'; | Type mismatch. | Dart |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
<p>output <b>world</p></b> | <p>output <b>world</b></p> | Nest properly. | HTML |
echo world test | echo 'world test' | Quote to prevent splitting. | Shell |
object Person {{ def main(args: Array[String]) = println("world") }} | object Person {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
if ($val = 25) | if ($val == 25) | Use ==. | Perl |
function foo(item)
print(item)
end | function foo(item)
print(item)
end | Correct. | Lua |
[58, 42, 50 | [58, 42, 50] | Close bracket. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
const obj:Person = {{name:'world'}}; | const obj:Person = {{name:'world', age:82}}; | Add missing property. | TypeScript |
print 'hello' | print('hello') | print needs parentheses. | Python |
var x = 85; | var x = 85; | Correct. | Dart |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
values[29] | if (values.indices.contains(29)) values[29] | Check index. | Kotlin |
let x = 93; let x = 27; | let x = 93; x = 27; | Duplicate declaration. | JavaScript |
if z = 65 | if z == 65 | Use ==. | Go |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
{{"id":"result" "name":12}} | {{"id":"result", "name":12}} | Add comma. | JSON |
if (a) console.log('yes') else console.log('no') | if (a) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
def handle():
print('value') | def handle():
print('value') | Indent function body. | Python |
let z: number | null = null; z.toFixed(75); | let z: number | null = null; if(z!==null) z.toFixed(75); | Null check. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<div><p>hello</div></p> | <div><p>hello</p></div> | Nest properly. | HTML |
let vec=vec![100,47,99]; let first=&vec[0]; vec.push(20); | let mut vec=vec![100,47,99]; let first=vec[0]; vec.push(20); | Copy instead of reference. | Rust |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
46data = 10 | data46 = 10 | Variable cannot start with digit. | Python |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
UPDATE items SET id='data' WHERE role=38 | UPDATE items SET id='data' WHERE role=38; | Add semicolon. | SQL |
if (index = 64) | if (index == 64) | Use ==. | C++ |
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