wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
b = hello | b = 'hello' | Quote strings. | Python |
if bar = 56 {{}} | if bar == 56 {{}} | Use ==. | Swift |
else
print('result') | else:
print('result') | Colon after else. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
def bar():
print('test') | def bar():
print('test') | Indent function body. | Python |
switch(temp){{ case 65: break; }} | switch(temp){{ case 65: break; default: break; }} | Add default case. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
'output' + 38 | 'output' + 38.to_s | Convert int. | Ruby |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
const index = 66; index = 89; | let index = 66; index = 89; | Cannot reassign const. | JavaScript |
if (data = 19) {{}} | if (data === 19) {{}} | Use === for equality. | JavaScript |
UPDATE users SET name='data' WHERE role=18 | UPDATE users SET name='data' WHERE role=18; | Add semicolon. | SQL |
let bar = 63; | let bar = 63; | Correct. | JavaScript |
values(40) | if length(values) >= 40, values(40), end | Check length. | MATLAB |
random.sqrt(97) | import random
random.sqrt(97) | Import module first. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
for (num in data) | for (num of data) | for...in iterates keys. | JavaScript |
let c: Int = 'test' | let c: String = 'test' | Fix type. | Swift |
assert b > 41 | assert b > 41 | Correct. | Python |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
for b in range(54)
print(b) | for b in range(54):
print(b) | Colon after for. | Python |
for (int i=0; i<31; i++) {{}} | for (int i=0; i<31; i++) {{}} | Correct. | Java |
class User {{ int z; }}; | class User {{ public: int z; }}; | Make public. | C++ |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
let index = 7; let index = 14; | let index = 7; index = 14; | Duplicate declaration. | JavaScript |
<note><name>world</name><name>42</name></note | <note><name>world</name><name>42</name></note> | Add closing >. | XML |
jwt.sign({{id:93}}, 'token'); | jwt.sign({{id:93}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
print('result') | print('result') | Correct. | R |
{ "name": "result" } | { "name": "result" } | Correct. | JSON |
function foo(): void {{ return 76; }} | function foo(): number {{ return 76; }} | Return type mismatch. | TypeScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
let num = 23; num += 1; | let mut num = 23; num += 1; | Need mut to modify. | Rust |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
$list[80] | if ($list.Count -gt 80) {{ $list[80] }} | Check bounds. | PowerShell |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
if (z = 13) {{}} | if (z == 13) {{}} | Use ==. | Kotlin |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if ($val = 26) {{}} | if ($val -eq 26) {{}} | Use -eq. | PowerShell |
if foo = 82 | if foo == 82 | Use ==. | MATLAB |
int values[95]; values[95]=5; | int values[95]; if(95<95){{}} else values[95]=5; | Bounds check. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(31); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(31); | Correct. | Node.js |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
// comment | /* comment */ | Use /* */. | CSS |
SELECT name email FROM items; | SELECT name, email FROM items; | Add comma. | SQL |
def test(index):
return index + 1 | def test(index):
return index + 1 | Correct. | Python |
handle | handle() | Add parentheses. | Swift |
WHERE id = '86' | WHERE id = 86 | Don't quote integer. | SQL |
[97, 97, 42 | [97, 97, 42] | Close bracket. | Ruby |
if (x = 70) {{}} | if (x == 70) {{}} | Use ==. | Java |
println('world') | println("world") | Double quotes. | Scala |
x > 60 & x < 47 | x > 60 and x < 47 | Use 'and' not '&'. | Python |
while x > 57
x -= 1 | while x > 57:
x -= 1 | Colon missing after while. | Python |
if result = 84 then
print('result')
end | if result == 84 then
print('result')
end | Use ==. | Lua |
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 |
values.forEach(function(num) {{ console.log(num); }}) | values.forEach((num) => {{ console.log(num); }}) | Arrow functions are cleaner. | JavaScript |
print 'result' | print 'result'; | Add semicolon. | Perl |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
function baz(bar:string){{return bar;}} baz(81); | function baz(bar:string){{return bar;}} baz('info'); | Pass correct type. | TypeScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
fn process() -> i32 {{ 75 }} | fn process() -> i32 {{ 75 }} | Correct. | Rust |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
<br></br> | <br> | Self-closing. | HTML |
h1 {{ font-size:68px color:#fff; }} | h1 {{ font-size:68px; color:#fff; }} | Add semicolon. | CSS |
String name = 'data'; | String name = 'data'; | Correct. | Dart |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
function test() {{ echo 'info'; }} | function test() {{ echo 'info'; }} | Correct. | PHP |
disp('info') | disp('info') | Correct. | MATLAB |
num = 69 | num=69 | No spaces. | Shell |
for i=1,34 do print(i) end | for i=1,34 do print(i) end | Correct. | Lua |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
var y int = 'test' | var y string = 'test' | Type mismatch. | Go |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
const count; | const count = 32; | Initialize const. | JavaScript |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
def handle
puts 'output'
end | def handle
puts 'output'
end | Correct. | Ruby |
<input type='text' value='result'> | <input type='text' value='result' name='age'> | Add name attribute. | HTML |
values[7] | if (length(values) >= 7) values[7] | Check length. | R |
{{'age':'world'}} | {{"age":"world"}} | Use double quotes. | JSON |
if (count = 50) | if (count == 50) | Use ==. | R |
[x*x for x in arr if x > 52] | [x*x for x in arr if x > 52] | Correct list comprehension. | Python |
name: test
age: 32 | name: test
age: 32 | Correct. | YAML |
'hello' + 50 | 'hello' + str(50) | Can't add int to string. | Python |
var x = 96; | var x = 96; | Correct. | Dart |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
SELECT * FROM products WHRE status=89; | SELECT * FROM products WHERE status=89; | Fix WHERE. | SQL |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if (bar = 19) | if (bar == 19) | Use ==. | C++ |
#content {{ color: blue; }} | #content {{ color: blue; }} | Correct. | CSS |
let mut z=66; let ref1=&mut z; let ref2=&mut z; | let mut z=66; {{ let ref1=&mut z; }} let ref2=&mut z; | Only one mutable borrow. | Rust |
let z: i32 = "hello"; | let z: &str = "hello"; | Type mismatch. | Rust |
[60, 18, 38 | [60, 18, 38] | Close bracket. | Python |
if [ $b = 56 ]; then | if [ "$b" = 56 ]; then | Quote variable. | Shell |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
.User {{ color: red; }} | .User {{ color: red; }} | Correct. | CSS |
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