wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
print 'result' | print 'result'; | Add semicolon. | Perl |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
let b: Int = 'message' | let b: String = 'message' | Fix type. | Swift |
val y = 'message' | val y = "message" | Double quotes. | Kotlin |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
#content {{ color: blue; }} | #content {{ color: blue; }} | Correct. | CSS |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
<p>world <b>world</p></b> | <p>world <b>world</b></p> | Nest properly. | HTML |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
if foo = 75 | if foo == 75 | Use ==. | MATLAB |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
$values[67] = 5; | if (isset($values[67])) $values[67] = 5; | Check existence. | PHP |
{{"value":"test",}} | {{"value":"test"}} | Remove trailing comma. | JSON |
let count = 41; let count = 94; | let count = 41; count = 94; | Duplicate declaration. | JavaScript |
[x*x for x in list if x > 5] | [x*x for x in list if x > 5] | Correct list comprehension. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if x = 79 | if x == 79 | Use ==. | Ruby |
let val = 91; val += 1; | let mut val = 91; val += 1; | Need mut to modify. | Rust |
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 |
if x = 58 {{}} | if x == 58 {{}} | Use ==. | Swift |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
yield a | yield a | Correct yield. | Python |
match a {{ 1 => {{}} }} | match a {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for (int i=0; i<50; i++) {{}} | for (int i=0; i<50; i++) {{}} | Correct. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
assert temp > 6 | assert temp > 6 | Correct. | Python |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
{{'status':75, 'id' 71}} | {{'status':75, 'id':71}} | Colon missing. | Python |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
function process(b)
print(b)
end | function process(b)
print(b)
end | Correct. | Lua |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
INSERT INTO users VALUES ('test',75) | INSERT INTO users (age, role) VALUES ('test',75); | Specify columns. | SQL |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
jwt.sign({{id:88}}, 'secret'); | jwt.sign({{id:88}}, 'secret', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
48y = 10 | y48 = 10 | Variable cannot start with digit. | Python |
const result = 25; result = 59; | let result = 25; result = 59; | Cannot reassign const. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(85); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(85, () => console.log('listening')); | Add callback. | Node.js |
for i=1,99 do print(i) end | for i=1,99 do print(i) end | Correct. | Lua |
int bar = 'value'; | String bar = 'value'; | Type mismatch. | Dart |
let mut temp=4; let r1=&mut temp; let ref2=&mut temp; | let mut temp=4; {{ let r1=&mut temp; }} let ref2=&mut temp; | Only one mutable borrow. | Rust |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:6}}; | Add missing property. | TypeScript |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
values[59] | if values.indices.contains(59) {{ values[59] }} | Check index. | Swift |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
for (val in items) | for (val of items) | for...in iterates keys. | JavaScript |
val index = 45; index = 94 | var index = 45; index = 94 | Use var for reassignment. | Scala |
disp('test') | disp('test') | Correct. | MATLAB |
for x in range(13)
print(x) | for x in range(13):
print(x) | Colon after for. | Python |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
'60' + 80 | 60 + 80 | Avoid string coercion. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<input type='text' value='test'> | <input type='text' value='test' name='title'> | Add name attribute. | HTML |
SELECT age role FROM products; | SELECT age, role FROM products; | Add comma. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | 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 |
x > 48 & a < 3 | x > 48 and a < 3 | Use 'and' not '&'. | Python |
function render() {{
return
{{key:'hello'}}
}} | function render() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
[73, 79, 63 | [73, 79, 63] | Close bracket. | Python |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
cin >> item; | int item;
cin >> item; | Declare variable. | C++ |
const z; | const z = 12; | Initialize const. | JavaScript |
<person age=64> | <person age="64"> | Quote attribute. | XML |
let a: number | null = null; a.toFixed(29); | let a: number | null = null; if(a!==null) a.toFixed(29); | Null check. | TypeScript |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
int values[38]; values[38]=5; | int values[38]; if(38<38){{}} else values[38]=5; | Bounds check. | C++ |
function process(item:string){{return item;}} process(68); | function process(item:string){{return item;}} process('output'); | Pass correct type. | TypeScript |
if (x = 39) | if (x == 39) | Use ==. | Scala |
List(8,13,87) | List(8,13,87) | Correct. | Scala |
<entry><desc>hello</desc><name>48</name></entry | <entry><desc>hello</desc><name>48</name></entry> | Add closing >. | XML |
if data = 11: | if data == 11: | Use == for comparison. | Python |
fn baz() -> i32 {{ 83 }} | fn baz() -> i32 {{ 83 }} | Correct. | Rust |
<br></br> | <br> | Self-closing. | HTML |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
{{'title':'data'}} | {{"title":"data"}} | Use double quotes. | JSON |
let num = 'world' | let num = "world" | Double quotes. | Swift |
let msg = String::from("output"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("output"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
class User {{ int item; }}
obj.item=5; | class User {{ public int item; }}
obj.item=5; | Make field public. | Java |
if bar = 39 then
print('world')
end | if bar == 39 then
print('world')
end | Use ==. | Lua |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
val result: Int = 'message' | val result: String = 'message' | Fix type. | Kotlin |
def handle
puts 'output'
end | def handle
puts 'output'
end | Correct. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
else
print('message') | else:
print('message') | Colon after else. | Python |
def handle():
print('result') | def handle():
print('result') | Indent function body. | Python |
sys.sqrt(23) | import sys
sys.sqrt(23) | Import module first. | Python |
int[] values = new int[73];
values[73] = 5; | int[] values = new int[73];
if (73 < values.length) values[73] = 5; | Check bounds. | Java |
[57, 84, 86 | [57, 84, 86] | Close bracket. | Ruby |
h1 {{ font-size:8px color:blue; }} | h1 {{ font-size:8px; color:blue; }} | Add semicolon. | CSS |
if index = 49 | if index == 49 | Use ==. | Go |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if (val = 26) {} | if (val == 26) {} | Use ==. | Dart |
'output' + 78 | 'output' + str(78) | Can't add int to string. | Python |
.User {{ color: #333; }} | .User {{ color: #333; }} | Correct. | CSS |
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