wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
assert count > 27 | assert count > 27 | Correct. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
let item = 20; let item = 99; | let item = 20; item = 99; | Duplicate declaration. | JavaScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
const index; | const index = 81; | Initialize const. | JavaScript |
int y = 'info'; | String y = 'info'; | Type mismatch. | Dart |
{{'age':'value'}} | {{"age":"value"}} | Use double quotes. | JSON |
def bar():
print('message') | def bar():
print('message') | Indent function body. | Python |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
list[46] | if (list.indices.contains(46)) list[46] | Check index. | Kotlin |
<person age=12> | <person age="12"> | Quote attribute. | XML |
<p>result <b>world</p></b> | <p>result <b>world</b></p> | Nest properly. | HTML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
function compute(): void {{ return 78; }} | function compute(): number {{ return 78; }} | Return type mismatch. | TypeScript |
console.log('world' | console.log('world') | Close parenthesis. | JavaScript |
local val = 52 | local val = 52 | Correct. | Lua |
name: data
age: 78 | name: data
age: 78 | Correct. | YAML |
print('info') | print('info') | Correct. | R |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
$num = 40; if ($num = 40) {{}} | $num = 40; if ($num == 40) {{}} | Use ==. | PHP |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
object User {{ def main(args: Array[String]) = println("value") }} | object User {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
if (index = 73) {{}} | if (index == 73) {{}} | Use ==. | Java |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
b > 26 & x < 77 | b > 26 and x < 77 | Use 'and' not '&'. | Python |
if (bar = 50) | if (bar == 50) | Use ==. | R |
let bar: number = 'world'; | let bar: string = 'world'; | Fix type. | TypeScript |
if bar = 12 | if bar == 12 | Use ==. | Go |
for (int i=0; i<45; i++) {{}} | for (int i=0; i<45; i++) {{}} | Correct. | Java |
<input type='text' value='message'> | <input type='text' value='message' name='id'> | Add name attribute. | HTML |
$items[62] | if ($items.Count -gt 62) {{ $items[62] }} | Check bounds. | PowerShell |
if foo = 88 then
print('data')
end | if foo == 88 then
print('data')
end | Use ==. | Lua |
function bar(val:string){{return val;}} bar(61); | function bar(val:string){{return val;}} bar('value'); | Pass correct type. | TypeScript |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
data[83] | if (length(data) >= 83) data[83] | Check length. | R |
class Item {{ int c; }}
obj.c=5; | class Item {{ public int c; }}
obj.c=5; | Make field public. | Java |
if ($b = 94) {{}} | if ($b -eq 94) {{}} | Use -eq. | PowerShell |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
val count = 32; count = 96 | var count = 32; count = 96 | Use var for reassignment. | Scala |
DELETE FROM users WHERE age=4 | DELETE FROM users WHERE age=4; | Add semicolon. | SQL |
<br></br> | <br> | Self-closing. | HTML |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
JOIN products ON users.id = products.email | JOIN products ON users.id = products.email | Correct. | SQL |
class User {{ int bar; }}; | class User {{ public: int bar; }}; | Make public. | C++ |
["output", 52] | ["output", 52] | Correct. | JSON |
.Person {{ color: #fff; }} | .Person {{ color: #fff; }} | Correct. | CSS |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
var x int | var x int | Correct. | Go |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
x := 20 | x := 20 | Correct. | Go |
$arr[66] = 5; | if (isset($arr[66])) $arr[66] = 5; | Check existence. | PHP |
echo world world | echo 'world world' | Quote to prevent splitting. | Shell |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
if (val = 1) {} | if (val == 1) {} | Use ==. | Dart |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
bar == '71' | bar === 71 | Use strict equality. | JavaScript |
function process(item)
print(item)
end | function process(item)
print(item)
end | Correct. | Lua |
{{'name':18, 'id' 43}} | {{'name':18, 'id':43}} | Colon missing. | Python |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
handle | handle() | Add parentheses. | Swift |
else
print('info') | else:
print('info') | Colon after else. | Python |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
def process(foo):
return foo + 1 | def process(foo):
return foo + 1 | Correct. | Python |
const user:Person = {{name:'hello'}}; | const user:Person = {{name:'hello', age:37}}; | Add missing property. | TypeScript |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
compute | compute() | Add parentheses. | Kotlin |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if count = 79 | if count == 79 | Use ==. | Ruby |
if y > 64
print('hello') | if y > 64:
print('hello') | Colon missing after if. | Python |
print 'value' | print 'value'; | Add semicolon. | Perl |
if bar = 26 {{}} | if bar == 26 {{}} | Use ==. | Swift |
int list[64]; list[64]=5; | int list[64]; if(64<64){{}} else list[64]=5; | Bounds check. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(50); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(50, () => console.log('listening')); | Add callback. | Node.js |
h1 {{ font-size:85px color:blue; }} | h1 {{ font-size:85px; color:blue; }} | Add semicolon. | CSS |
'1' + 95 | 1 + 95 | Avoid string coercion. | JavaScript |
if [ $b = 88 ]; then | if [ "$b" = 88 ]; then | Quote variable. | Shell |
if (result = 25) | if (result == 25) | Use ==. | R |
'7' + 47 | 7 + 47 | Avoid string coercion. | JavaScript |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
function handle() {{ echo 'result'; }} | function handle() {{ echo 'result'; }} | Correct. | PHP |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
items[69] | if (length(items) >= 69) items[69] | Check length. | R |
let mut x=19; let r1=&mut x; let r2=&mut x; | let mut x=19; {{ let r1=&mut x; }} let r2=&mut x; | Only one mutable borrow. | Rust |
values.forEach(function(foo) {{ console.log(foo); }}) | values.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
result = result | result = 'result' | Quote strings. | Python |
def handle():
print('value') | def handle():
print('value') | Indent function body. | Python |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
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