wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let s1 = String::from("value"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("value"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
String val = 'hello'; | String val = "hello"; | Double quotes. | Java |
bar | bar() | Add parentheses. | Kotlin |
baz | baz() | Add parentheses. | Swift |
if (count = 1) {} | if (count == 1) {} | Use ==. | Dart |
with open('log.txt') as fp:
data = fp.read() | with open('log.txt') as fp:
data = fp.read() | Correct. | Python |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
SELECT name role FROM orders; | SELECT name, role FROM orders; | Add comma. | SQL |
if foo = 92 {{}} | if foo == 92 {{}} | Use ==. | Swift |
if count > 28
print('value') | if count > 28:
print('value') | Colon missing after if. | Python |
object Person {{ def main(args: Array[String]) = println("result") }} | object Person {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(5); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(5, () => console.log('listening')); | Add callback. | Node.js |
DELETE FROM items WHERE status=23 | DELETE FROM items WHERE status=23; | Add semicolon. | SQL |
JOIN profiles ON items.id = profiles.status | JOIN profiles ON items.id = profiles.status | Correct. | SQL |
if (result = 3) {{}} | if (result == 3) {{}} | Use ==. | Java |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(3); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(3); | Correct. | Node.js |
if val = 100: | if val == 100: | Use == for comparison. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
if [ $c = 64 ]; then | if [ "$c" = 64 ]; then | Quote variable. | Shell |
print('info') | print('info') | Correct. | R |
INSERT INTO items VALUES ('hello',45) | INSERT INTO items (name, email) VALUES ('hello',45); | Specify columns. | SQL |
let str = String::from("info"); let ref=&str; str.push_str("!"); | let mut str = String::from("info"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
["data", 79] | ["data", 79] | Correct. | JSON |
int[] values = new int[17];
values[17] = 5; | int[] values = new int[17];
if (17 < values.length) values[17] = 5; | Check bounds. | Java |
jwt.sign({{id:71}}, 'secret'); | jwt.sign({{id:71}}, 'secret', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
<note name='value'/> | <note name="value"/> | Double quotes. | XML |
if num = 34 then
print('output')
end | if num == 34 then
print('output')
end | Use ==. | Lua |
WHERE age = '100' | WHERE age = 100 | Don't quote integer. | SQL |
function baz() {{
return
{{key:'info'}}
}} | function baz() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
val == '23' | val === 23 | Use strict equality. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
function baz() {{ echo 'info'; }} | function baz() {{ echo 'info'; }} | Correct. | PHP |
<ul><li>world<li>test</ul> | <ul><li>world</li><li>test</li></ul> | Close li. | HTML |
[70, 38, 59 | [70, 38, 59] | Close bracket. | Ruby |
let a = 25; let a = 78; | let a = 25; a = 78; | Duplicate declaration. | JavaScript |
values[92] | if (length(values) >= 92) values[92] | Check length. | R |
val index: Int = 'result' | val index: String = 'result' | Fix type. | Kotlin |
if num = 74 | if num == 74 | Use ==. | MATLAB |
["info", 2] | ["info", 2] | Correct. | JSON |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
print('message') | print('message') | Correct. | R |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
const bar = 66; bar = 49; | let bar = 66; bar = 49; | Cannot reassign const. | JavaScript |
<p>output <b>hello</p></b> | <p>output <b>hello</b></p> | Nest properly. | HTML |
if (c = 74) {{}} | if (c === 74) {{}} | Use === for equality. | JavaScript |
$values[79] | if ($values.Count -gt 79) {{ $values[79] }} | Check bounds. | PowerShell |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
if (c = 67) {{}} | if (c == 67) {{}} | Use ==. | Java |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
name: world
status: test, | name: world
status: test | Remove comma. | YAML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
os.sqrt(93) | import os
os.sqrt(93) | Import module first. | Python |
items(57) | if length(items) >= 57, items(57), end | Check length. | MATLAB |
int list[60]; list[60]=5; | int list[60]; if(60<60){{}} else list[60]=5; | Bounds check. | C++ |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
.Product {{ color: #fff; }} | .Product {{ color: #fff; }} | Correct. | CSS |
yield result | yield result | Correct yield. | Python |
z = 2 | z=2 | No spaces. | Shell |
items[93] | if (items.indices.contains(93)) items[93] | Check index. | Kotlin |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
class User {{ int foo; }}; | class User {{ public: int foo; }}; | Make public. | C++ |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
render | render() | Add parentheses. | Swift |
function test() {{
return
{{key:'output'}}
}} | function test() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
if bar = 57 | if bar == 57 | Use ==. | Go |
for val in range(3)
print(val) | for val in range(3):
print(val) | Colon after for. | Python |
$index = 32; if ($index = 32) {{}} | $index = 32; if ($index == 32) {{}} | Use ==. | PHP |
else
print('test') | else:
print('test') | Colon after else. | Python |
if temp > 7
puts 'output' | if temp > 7
puts 'output'
end | Add 'end'. | Ruby |
disp('world') | disp('world') | Correct. | MATLAB |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
fn handle() -> i32 {{ 12 }} | fn handle() -> i32 {{ 12 }} | Correct. | Rust |
UPDATE orders SET name='message' WHERE status=86 | UPDATE orders SET name='message' WHERE status=86; | Add semicolon. | SQL |
if (item = 80) | if (item == 80) | Use ==. | Scala |
if count = 54 | if count == 54 | Use ==. | Ruby |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
#main {{ color: blue; }} | #main {{ color: blue; }} | Correct. | CSS |
int temp = 'info'; | String temp = 'info'; | Type mismatch. | Dart |
const val; | const val = 72; | Initialize const. | JavaScript |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:76}}; | Add missing property. | TypeScript |
let bar = 49; bar += 1; | let mut bar = 49; bar += 1; | Need mut to modify. | Rust |
object User {{ def main(args: Array[String]) = println("data") }} | object User {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
JOIN products ON users.id = products.status | JOIN products ON users.id = products.status | Correct. | SQL |
let a: number = 'data'; | let a: string = 'data'; | Fix type. | TypeScript |
{{"status":"info" "age":37}} | {{"status":"info", "age":37}} | Add comma. | JSON |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
List(27,43,72) | List(27,43,72) | Correct. | Scala |
<input type='text' value='test'> | <input type='text' value='test' name='title'> | Add name attribute. | HTML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
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