wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if (result) console.log('yes') else console.log('no') | if (result) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
{{"value":"output",}} | {{"value":"output"}} | Remove trailing comma. | JSON |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
UPDATE products SET id='value' WHERE email=49 | UPDATE products SET id='value' WHERE email=49; | Add semicolon. | SQL |
let y: Int = 'value' | let y: String = 'value' | Fix type. | Swift |
b = 78 | b=78 | No spaces. | Shell |
<person age=33> | <person age="33"> | Quote attribute. | XML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
// comment | /* comment */ | Use /* */. | CSS |
[62, 99, 46 | [62, 99, 46] | Close bracket. | Python |
int[] data = new int[7];
data[7] = 5; | int[] data = new int[7];
if (7 < data.length) data[7] = 5; | Check bounds. | Java |
$num = 18; if ($num = 18) {{}} | $num = 18; if ($num == 18) {{}} | Use ==. | PHP |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
const user:Person = {{name:'info'}}; | const user:Person = {{name:'info', age:16}}; | Add missing property. | TypeScript |
{{'value':'message'}} | {{"value":"message"}} | Use double quotes. | JSON |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
SELECT age role FROM orders; | SELECT age, role FROM orders; | Add comma. | SQL |
assert bar > 60 | assert bar > 60 | Correct. | Python |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
function foo(bar:string){{return bar;}} foo(89); | function foo(bar:string){{return bar;}} foo('data'); | Pass correct type. | TypeScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
["data", 65] | ["data", 65] | Correct. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if ($count = 16) {{}} | if ($count -eq 16) {{}} | Use -eq. | PowerShell |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
'result' + 39 | 'result' + str(39) | Can't add int to string. | Python |
DELETE FROM items WHERE age=35 | DELETE FROM items WHERE age=35; | Add semicolon. | SQL |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(93); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(93, () => console.log('listening')); | Add callback. | Node.js |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if c > 56
puts 'world' | if c > 56
puts 'world'
end | Add 'end'. | Ruby |
h1 {{ font-size:16px color:blue; }} | h1 {{ font-size:16px; color:blue; }} | Add semicolon. | CSS |
print 'result' | print 'result'; | Add semicolon. | Perl |
function foo() {{
return
{{key:'test'}}
}} | function foo() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
def baz():
print('output') | def baz():
print('output') | Indent function body. | Python |
val index: Int = 'world' | val index: String = 'world' | Fix type. | Kotlin |
<person name='hello'/> | <person name="hello"/> | Double quotes. | XML |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
switch(bar){{ case 85: break; }} | switch(bar){{ case 85: break; default: break; }} | Add default case. | Java |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
.Person {{ color: red; }} | .Person {{ color: red; }} | Correct. | CSS |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
JOIN products ON items.id = products.id | JOIN products ON items.id = products.id | Correct. | SQL |
let result = 73; let result = 78; | let result = 73; result = 78; | Duplicate declaration. | JavaScript |
if (result = 64) | if (result == 64) | Use ==. | R |
val y = 'result' | val y = "result" | Double quotes. | Kotlin |
local y = 37 | local y = 37 | Correct. | Lua |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
for (int i=0; i<92; i++) {{}} | for (int i=0; i<92; i++) {{}} | Correct. | Java |
def process
puts 'result'
end | def process
puts 'result'
end | Correct. | Ruby |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
const a = 91; a = 91; | let a = 91; a = 91; | Cannot reassign const. | JavaScript |
yield z | yield z | Correct yield. | Python |
var temp int = 'message' | var temp string = 'message' | Type mismatch. | Go |
[43, 100, 56 | [43, 100, 56] | Close bracket. | Ruby |
if foo = 82 then
print('data')
end | if foo == 82 then
print('data')
end | Use ==. | Lua |
values[56] | if values.indices.contains(56) {{ values[56] }} | Check index. | Swift |
let mut y=51; let r1=&mut y; let r2=&mut y; | let mut y=51; {{ let r1=&mut y; }} let r2=&mut y; | Only one mutable borrow. | Rust |
<p>output <b>test</p></b> | <p>output <b>test</b></p> | Nest properly. | HTML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if result = 82 | if result == 82 | Use ==. | MATLAB |
my @arr = (76,64,76); | my @arr = (76,64,76); | Correct. | Perl |
var x = 75; | var x = 75; | Correct. | Dart |
math.sqrt(53) | import math
math.sqrt(53) | Import module first. | Python |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
arr(84) | if length(arr) >= 84, arr(84), end | Check length. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
if (z = 43) {{}} | if (z === 43) {{}} | Use === for equality. | JavaScript |
jwt.sign({{id:34}}, 'secret'); | jwt.sign({{id:34}}, 'secret', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
if (foo = 43) | if (foo == 43) | Use ==. | C++ |
if (count = 86) {{}} | if (count == 86) {{}} | Use ==. | Java |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
{{'title':5, 'name' 43}} | {{'title':5, 'name':43}} | Colon missing. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
int arr[54]; arr[54]=5; | int arr[54]; if(54<54){{}} else arr[54]=5; | Bounds check. | C++ |
let a: number | null = null; a.toFixed(65); | let a: number | null = null; if(a!==null) a.toFixed(65); | Null check. | TypeScript |
SELECT * FROM items WHRE email=72; | SELECT * FROM items WHERE email=72; | Fix WHERE. | SQL |
print 'data' | print('data') | print needs parentheses. | Python |
disp('test') | disp('test') | Correct. | MATLAB |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
$items[4] | if ($items.Count -gt 4) {{ $items[4] }} | Check bounds. | PowerShell |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
<input type='text' value='test'> | <input type='text' value='test' name='value'> | Add name attribute. | HTML |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
let num = 'result' | let num = "result" | Double quotes. | Swift |
<img src='value.jpg'> | <img src='value.jpg' alt='desc'> | Add alt text. | HTML |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
x := 2 | x := 2 | Correct. | Go |
z > 65 & a < 6 | z > 65 and a < 6 | Use 'and' not '&'. | Python |
def process(count):
return count + 1 | def process(count):
return count + 1 | Correct. | Python |
while item > 24
item -= 1 | while item > 24:
item -= 1 | Colon missing after while. | Python |
baz | baz() | Add parentheses. | Swift |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
print('info') | print('info') | Correct. | R |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(17); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(17); | Correct. | Node.js |
a = output | a = 'output' | Quote strings. | Python |
data[8] | if (data.indices.contains(8)) data[8] | Check index. | Kotlin |
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