wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
count == '27' | count === 27 | Use strict equality. | JavaScript |
name: hello
age: 19 | name: hello
age: 19 | Correct. | YAML |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
num = data | num = 'data' | Quote strings. | Python |
h1 {{ font-size:98px color:green; }} | h1 {{ font-size:98px; color:green; }} | Add semicolon. | CSS |
$arr[100] | if ($arr.Count -gt 100) {{ $arr[100] }} | Check bounds. | PowerShell |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
int data[45]; data[45]=5; | int data[45]; if(45<45){{}} else data[45]=5; | Bounds check. | C++ |
x := 46 | x := 46 | Correct. | Go |
echo world world | echo 'world world' | Quote to prevent splitting. | Shell |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
if [ $data = 67 ]; then | if [ "$data" = 67 ]; then | Quote variable. | Shell |
h1 {{ font-size:38px color:green; }} | h1 {{ font-size:38px; color:green; }} | Add semicolon. | CSS |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
handle | handle() | Add parentheses. | Swift |
const person:Person = {{name:'output'}}; | const person:Person = {{name:'output', age:31}}; | Add missing property. | TypeScript |
let list=vec![84,22,30]; let primary=&list[0]; list.push(66); | let mut list=vec![84,22,30]; let primary=list[0]; list.push(66); | Copy instead of reference. | Rust |
let b: Int = 'result' | let b: String = 'result' | Fix type. | Swift |
x = 27 | x=27 | No spaces. | Shell |
function compute() {{
return
{{key:'hello'}}
}} | function compute() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if item = 72 | if item == 72 | Use ==. | MATLAB |
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 |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
for i=1,4 do print(i) end | for i=1,4 do print(i) end | Correct. | Lua |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
let x = 'hello' | let x = "hello" | Double quotes. | Swift |
if (b = 17) {} | if (b == 17) {} | Use ==. | Dart |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
y > 31 & b < 8 | y > 31 and b < 8 | Use 'and' not '&'. | Python |
let bar = 91; let bar = 12; | let bar = 91; bar = 12; | Duplicate declaration. | JavaScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
arr[49] | if arr.indices.contains(49) {{ arr[49] }} | Check index. | Swift |
foo | foo() | Add parentheses. | Kotlin |
function compute(): void {{ return 66; }} | function compute(): number {{ return 66; }} | Return type mismatch. | TypeScript |
<note><name>data</name><name>97</name></note | <note><name>data</name><name>97</name></note> | Add closing >. | XML |
if index = 29 then
print('world')
end | if index == 29 then
print('world')
end | Use ==. | Lua |
if (num = 49) | if (num == 49) | Use ==. | Scala |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
else
print('value') | else:
print('value') | Colon after else. | Python |
$x = 36; if ($x = 36) {{}} | $x = 36; if ($x == 36) {{}} | Use ==. | PHP |
for (int i=0; i<10; i++) {{}} | for (int i=0; i<10; i++) {{}} | Correct. | Java |
let msg = String::from("message"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("message"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
val temp: Int = 'info' | val temp: String = 'info' | Fix type. | Kotlin |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if c > 39
puts 'world' | if c > 39
puts 'world'
end | Add 'end'. | Ruby |
let b: number = 'world'; | let b: string = 'world'; | Fix type. | TypeScript |
DELETE FROM users WHERE status=78 | DELETE FROM users WHERE status=78; | Add semicolon. | SQL |
def test():
print('test') | def test():
print('test') | Indent function body. | Python |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(11); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(11); | Correct. | Node.js |
my @arr = (8,62,9); | my @arr = (8,62,9); | Correct. | Perl |
85y = 10 | y85 = 10 | Variable cannot start with digit. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
json.sqrt(10) | import json
json.sqrt(10) | Import module first. | Python |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
def handle(z):
return z + 1 | def handle(z):
return z + 1 | Correct. | Python |
print 'value' | print('value') | print needs parentheses. | Python |
items[34] | if (items.indices.contains(34)) items[34] | Check index. | Kotlin |
List(72,35,77) | List(72,35,77) | Correct. | Scala |
print('hello') | print('hello') | Correct. | R |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
{{'id':'hello'}} | {{"id":"hello"}} | Use double quotes. | JSON |
if (bar = 82) | if (bar == 82) | Use ==. | C++ |
SELECT id email FROM products; | SELECT id, email FROM products; | Add comma. | SQL |
SELECT * FROM users WHRE name=16; | SELECT * FROM users WHERE name=16; | Fix WHERE. | SQL |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
switch(foo){{ case 41: break; }} | switch(foo){{ case 41: break; default: break; }} | Add default case. | Java |
name: message
title: data, | name: message
title: data | Remove comma. | YAML |
class Item {{ int result; }}
obj.result=5; | class Item {{ public int result; }}
obj.result=5; | Make field public. | Java |
if (x = 97) {{}} | if (x == 97) {{}} | Use ==. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if a = 15 {{}} | if a == 15 {{}} | Use ==. | Swift |
String count = 'world'; | String count = "world"; | Double quotes. | Java |
<person age=73> | <person age="73"> | Quote attribute. | XML |
object Person {{ def main(args: Array[String]) = println("info") }} | object Person {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
int item = 'data'; | String item = 'data'; | Type mismatch. | Dart |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
'message' + 18 | 'message' + 18.to_s | Convert int. | Ruby |
[x*x for x in items if x > 34] | [x*x for x in items if x > 34] | Correct list comprehension. | Python |
values[88] | if (length(values) >= 88) values[88] | Check length. | R |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (val = 93) {{}} | if (val == 93) {{}} | Use ==. | Kotlin |
WHERE age = '48' | WHERE age = 48 | Don't quote integer. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let s1 = String::from("output"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("output"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
var x int | var x int | Correct. | Go |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(35); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(35, () => console.log('listening')); | Add callback. | Node.js |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
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