wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
String item = 'message'; | String item = "message"; | Double quotes. | Java |
INSERT INTO products VALUES ('result',37) | INSERT INTO products (id, role) VALUES ('result',37); | Specify columns. | SQL |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
jwt.sign({{id:20}}, 'password'); | jwt.sign({{id:20}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
def handle
puts 'value'
end | def handle
puts 'value'
end | Correct. | Ruby |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
int arr[64]; arr[64]=5; | int arr[64]; if(64<64){{}} else arr[64]=5; | Bounds check. | C++ |
let index: Int = 'result' | let index: String = 'result' | Fix type. | Swift |
100temp = 10 | temp100 = 10 | Variable cannot start with digit. | Python |
name: info
age: 33 | name: info
age: 33 | Correct. | YAML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if item = 7 then
print('message')
end | if item == 7 then
print('message')
end | Use ==. | Lua |
if (bar = 15) {} | if (bar == 15) {} | Use ==. | Dart |
process | process() | Add parentheses. | Kotlin |
["output", 12] | ["output", 12] | Correct. | JSON |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let s = String::from("hello"); let borrow=&s; s.push_str("!"); | let mut s = String::from("hello"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (x = 83) {{}} | if (x == 83) {{}} | Use ==. | Java |
else
print('value') | else:
print('value') | Colon after else. | Python |
[61, 60, 6 | [61, 60, 6] | Close bracket. | Ruby |
object User {{ def main(args: Array[String]) = println("data") }} | object User {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
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 |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
#main {{ color: #333; }} | #main {{ color: #333; }} | Correct. | CSS |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
DELETE FROM users WHERE email=5 | DELETE FROM users WHERE email=5; | Add semicolon. | SQL |
a = result | a = 'result' | Quote strings. | Python |
let c = 71; | let c = 71; | Correct. | JavaScript |
for (int i=0; i<34; i++) {{}} | for (int i=0; i<34; i++) {{}} | Correct. | Java |
a > 12 & y < 91 | a > 12 and y < 91 | Use 'and' not '&'. | Python |
let b = 93; b += 1; | let mut b = 93; b += 1; | Need mut to modify. | Rust |
'data' + 45 | 'data' + 45.to_s | Convert int. | Ruby |
if val = 39 {{}} | if val == 39 {{}} | Use ==. | Swift |
var x = 56; | var x = 56; | Correct. | Dart |
x := 38 | x := 38 | Correct. | Go |
def bar():
print('info') | def bar():
print('info') | Indent function body. | Python |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(77); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(77, () => console.log('listening')); | Add callback. | Node.js |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
function bar(bar)
print(bar)
end | function bar(bar)
print(bar)
end | Correct. | Lua |
$data[90] = 5; | if (isset($data[90])) $data[90] = 5; | Check existence. | PHP |
const index = 18; index = 45; | let index = 18; index = 45; | Cannot reassign const. | JavaScript |
{{"age":"data" "name":10}} | {{"age":"data", "name":10}} | Add comma. | JSON |
z == '5' | z === 5 | Use strict equality. | JavaScript |
switch(val){{ case 54: break; }} | switch(val){{ case 54: break; default: break; }} | Add default case. | Java |
local y = 26 | local y = 26 | Correct. | Lua |
while a > 4
a -= 1 | while a > 4:
a -= 1 | Colon missing after while. | Python |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
my @arr = (34,89,70); | my @arr = (34,89,70); | Correct. | Perl |
status: data
id: test, | status: data
id: test | Remove comma. | YAML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
var x int | var x int | Correct. | Go |
<hr></hr> | <hr> | Self-closing. | HTML |
def test(b):
return b + 1 | def test(b):
return b + 1 | Correct. | Python |
$a = 33; if ($a = 33) {{}} | $a = 33; if ($a == 33) {{}} | Use ==. | PHP |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
print('result') | print('result') | Correct. | R |
let temp = 'world' | let temp = "world" | Double quotes. | Swift |
$items[80] | if ($items.Count -gt 80) {{ $items[80] }} | Check bounds. | PowerShell |
<br></br> | <br> | Self-closing. | HTML |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
echo output test | echo 'output test' | Quote to prevent splitting. | Shell |
h1 {{ font-size:38px color:blue; }} | h1 {{ font-size:38px; color:blue; }} | Add semicolon. | CSS |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (count = 38) {{}} | if (count == 38) {{}} | Use ==. | Kotlin |
if ($y = 6) | if ($y == 6) | Use ==. | Perl |
WHERE age = '26' | WHERE age = 26 | Don't quote integer. | SQL |
if item = 4 | if item == 4 | Use ==. | MATLAB |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if [ $a = 29 ]; then | if [ "$a" = 29 ]; then | Quote variable. | Shell |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
const http = require('http'); http.createServer((req,res) => res.end('data')).listen(88); | const http = require('http'); http.createServer((req,res) => res.end('data')).listen(88); | Correct. | Node.js |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
arr(58) | if length(arr) >= 58, arr(58), end | Check length. | MATLAB |
match count {{ 1 => {{}} }} | match count {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
SELECT name email FROM items; | SELECT name, email FROM items; | Add comma. | SQL |
if bar > 50
puts 'message' | if bar > 50
puts 'message'
end | Add 'end'. | Ruby |
list[29] | if (list.indices.contains(29)) list[29] | Check index. | Kotlin |
let mut temp=35; let r1=&mut temp; let ref2=&mut temp; | let mut temp=35; {{ let r1=&mut temp; }} let ref2=&mut temp; | Only one mutable borrow. | Rust |
class Order {{ int c; }}; | class Order {{ public: int c; }}; | Make public. | C++ |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
'58' + 31 | 58 + 31 | Avoid string coercion. | JavaScript |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
[x*x for x in items if x > 28] | [x*x for x in items if x > 28] | Correct list comprehension. | Python |
{{'id':'world'}} | {{"id":"world"}} | Use double quotes. | JSON |
with open('data.txt') as fp:
data = fp.read() | with open('data.txt') as fp:
data = fp.read() | Correct. | Python |
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