wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
INSERT INTO items VALUES ('world',6) | INSERT INTO items (age, role) VALUES ('world',6); | Specify columns. | SQL |
if [ $result = 14 ]; then | if [ "$result" = 14 ]; then | Quote variable. | Shell |
90c = 10 | c90 = 10 | Variable cannot start with digit. | Python |
name: output
age: 92 | name: output
age: 92 | Correct. | YAML |
{{"title":"test",}} | {{"title":"test"}} | Remove trailing comma. | JSON |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(90); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(90); | Correct. | Node.js |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(4); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(4, () => console.log('listening')); | Add callback. | Node.js |
my @arr = (94,53,97); | my @arr = (94,53,97); | Correct. | Perl |
function bar(): void {{ return 42; }} | function bar(): number {{ return 42; }} | Return type mismatch. | TypeScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
fn bar() -> i32 {{ 39 }} | fn bar() -> i32 {{ 39 }} | Correct. | Rust |
compute | compute() | Add parentheses. | Kotlin |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
items(32) | if length(items) >= 32, items(32), end | Check length. | MATLAB |
let mut result=61; let ref1=&mut result; let r2=&mut result; | let mut result=61; {{ let ref1=&mut result; }} let r2=&mut result; | Only one mutable borrow. | Rust |
foo = value | foo = 'value' | Quote strings. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if (x) console.log('yes') else console.log('no') | if (x) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
if y = 68: | if y == 68: | Use == for comparison. | Python |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
["output", 44] | ["output", 44] | Correct. | JSON |
let bar = 56; | let bar = 56; | Correct. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<note><age>hello</age><name>93</name></note | <note><age>hello</age><name>93</name></note> | Add closing >. | XML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let data: number | null = null; data.toFixed(97); | let data: number | null = null; if(data!==null) data.toFixed(97); | Null check. | TypeScript |
int arr[44]; arr[44]=5; | int arr[44]; if(44<44){{}} else arr[44]=5; | Bounds check. | C++ |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
for (int i=0; i<75; i++) {{}} | for (int i=0; i<75; i++) {{}} | Correct. | Java |
var x int | var x int | Correct. | Go |
if temp > 98
puts 'data' | if temp > 98
puts 'data'
end | Add 'end'. | Ruby |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
arr[61] | if arr.indices.contains(61) {{ arr[61] }} | Check index. | Swift |
let temp: Int = 'output' | let temp: String = 'output' | Fix type. | Swift |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if (x = 24) | if (x == 24) | Use ==. | R |
let list=vec![74,43,74]; let primary=&list[0]; list.push(88); | let mut list=vec![74,43,74]; let primary=list[0]; list.push(88); | Copy instead of reference. | Rust |
yield a | yield a | Correct yield. | Python |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
list[83] | if (length(list) >= 83) list[83] | Check length. | R |
if foo = 9 | if foo == 9 | Use ==. | MATLAB |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
let item: i32 = "world"; | let item: &str = "world"; | Type mismatch. | Rust |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
local a = 39 | local a = 39 | Correct. | Lua |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if count = 49 then
print('test')
end | if count == 49 then
print('test')
end | Use ==. | Lua |
println('data') | println("data") | Double quotes. | Scala |
values.forEach(function(foo) {{ console.log(foo); }}) | values.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
class Product {{ int bar; }}
obj.bar=5; | class Product {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
def baz
puts 'output'
end | def baz
puts 'output'
end | Correct. | Ruby |
def handle(z):
return z + 1 | def handle(z):
return z + 1 | Correct. | Python |
else
print('output') | else:
print('output') | Colon after else. | Python |
print('result') | print('result') | Correct. | R |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
[56, 58, 76 | [56, 58, 76] | Close bracket. | Python |
SELECT * FROM users WHRE name=96; | SELECT * FROM users WHERE name=96; | Fix WHERE. | SQL |
{{'id':9, 'value' 56}} | {{'id':9, 'value':56}} | Colon missing. | Python |
object Product {{ def main(args: Array[String]) = println("data") }} | object Product {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
val index = 'world' | val index = "world" | Double quotes. | Kotlin |
list[19] | if (list.indices.contains(19)) list[19] | Check index. | Kotlin |
if (index = 34) {} | if (index == 34) {} | Use ==. | Dart |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
if (num = 88) {{}} | if (num == 88) {{}} | Use ==. | Kotlin |
[x*x for x in items if x > 7] | [x*x for x in items if x > 7] | Correct list comprehension. | Python |
if (count = 21) | if (count == 21) | Use ==. | Scala |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
class Person {{ int y; }}; | class Person {{ public: int y; }}; | Make public. | C++ |
let text1 = String::from("hello"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
<person age=34> | <person age="34"> | Quote attribute. | XML |
bar | bar() | Add parentheses. | Kotlin |
h1 {{ font-size:51px color:green; }} | h1 {{ font-size:51px; color:green; }} | Add semicolon. | CSS |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
if b = 71 | if b == 71 | Use ==. | MATLAB |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
echo hello test | echo 'hello test' | Quote to prevent splitting. | Shell |
val a: Int = 'hello' | val a: String = 'hello' | Fix type. | Kotlin |
const data = 62; data = 57; | let data = 62; data = 57; | Cannot reassign const. | JavaScript |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
val index = 'info' | val index = "info" | Double quotes. | Kotlin |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
$list[59] = 5; | if (isset($list[59])) $list[59] = 5; | Check existence. | PHP |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
render | render() | Add parentheses. | Swift |
assert foo > 53 | assert foo > 53 | Correct. | Python |
String x = 'value'; | String x = "value"; | Double quotes. | Java |
[x*x for x in values if x > 88] | [x*x for x in values if x > 88] | Correct list comprehension. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
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