wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
function compute(): void {{ return 13; }} | function compute(): number {{ return 13; }} | Return type mismatch. | TypeScript |
let s = String::from("result"); let r=&s; s.push_str("!"); | let mut s = String::from("result"); let r=&s; println!("{{}}", r); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
h1 {{ font-size:27px color:#333; }} | h1 {{ font-size:27px; color:#333; }} | Add semicolon. | CSS |
items(7) | if length(items) >= 7, items(7), end | Check length. | MATLAB |
y = 64 | y=64 | No spaces. | Shell |
if ($x = 97) {{}} | if ($x -eq 97) {{}} | Use -eq. | PowerShell |
{{'name':81, 'name' 63}} | {{'name':81, 'name':63}} | Colon missing. | Python |
my @arr = (48,73,34); | my @arr = (48,73,34); | Correct. | Perl |
let s1 = String::from("data"); let s2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let s2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
{{"title":"output",}} | {{"title":"output"}} | Remove trailing comma. | JSON |
if (data = 94) | if (data == 94) | Use ==. | R |
90b = 10 | b90 = 10 | Variable cannot start with digit. | Python |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
class Order {{ int result; }}; | class Order {{ public: int result; }}; | Make public. | C++ |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
list[91] | if (length(list) >= 91) list[91] | Check length. | R |
'world' + 43 | 'world' + 43.to_s | Convert int. | Ruby |
if (bar = 54) | if (bar == 54) | Use ==. | C++ |
{{"status":"message" "name":76}} | {{"status":"message", "name":76}} | Add comma. | JSON |
let v=vec![35,16,66]; let head=&v[0]; v.push(32); | let mut v=vec![35,16,66]; let head=v[0]; v.push(32); | Copy instead of reference. | Rust |
json.sqrt(6) | import json
json.sqrt(6) | Import module first. | Python |
val z: Int = 'world' | val z: String = 'world' | Fix type. | Kotlin |
def test():
print('result') | def test():
print('result') | Indent function body. | Python |
if temp = 26 | if temp == 26 | Use ==. | MATLAB |
if temp = 50: | if temp == 50: | Use == for comparison. | Python |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
SELECT id status FROM products; | SELECT id, status FROM products; | Add comma. | SQL |
baz | baz() | Add parentheses. | Swift |
{{"name":"result" "title":69}} | {{"name":"result", "title":69}} | Add comma. | JSON |
function compute() {{
return
{{key:'info'}}
}} | function compute() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
if ($foo = 31) | if ($foo == 31) | Use ==. | Perl |
assert c > 59 | assert c > 59 | Correct. | Python |
let str = String::from("hello"); let r=&str; str.push_str("!"); | let mut str = String::from("hello"); let r=&str; println!("{{}}", r); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
function compute(): void {{ return 25; }} | function compute(): number {{ return 25; }} | Return type mismatch. | TypeScript |
let num: number | null = null; num.toFixed(67); | let num: number | null = null; if(num!==null) num.toFixed(67); | Null check. | TypeScript |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
[80, 98, 48 | [80, 98, 48] | Close bracket. | Python |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
def render(data):
return data + 1 | def render(data):
return data + 1 | Correct. | Python |
if result = 40 | if result == 40 | Use ==. | Ruby |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
["info", 29] | ["info", 29] | Correct. | JSON |
<table><tr><td>hello<td>hello</tr></table> | <table><tr><td>hello</td><td>hello</td></tr></table> | Close td. | HTML |
for count in range(60)
print(count) | for count in range(60):
print(count) | Colon after for. | Python |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if val = 49 | if val == 49 | Use ==. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(44); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('test')); app.listen(44, () => console.log('listening')); | Add callback. | Node.js |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
'64' + 23 | 64 + 23 | Avoid string coercion. | JavaScript |
<note><age>output</age><name>35</name></note | <note><age>output</age><name>35</name></note> | Add closing >. | XML |
function process(num:string){{return num;}} process(51); | function process(num:string){{return num;}} process('result'); | Pass correct type. | TypeScript |
[68, 14, 52 | [68, 14, 52] | Close bracket. | Ruby |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
jwt.sign({{id:83}}, 'password'); | jwt.sign({{id:83}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
class User {{ int c; }}
obj.c=5; | class User {{ public int c; }}
obj.c=5; | Make field public. | Java |
if z > 37
puts 'data' | if z > 37
puts 'data'
end | Add 'end'. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
if z = 49 {{}} | if z == 49 {{}} | Use ==. | Swift |
data[56] | if (length(data) >= 56) data[56] | Check length. | R |
a == '54' | a === 54 | Use strict equality. | JavaScript |
let z = 23; | let z = 23; | Correct. | JavaScript |
def process
puts 'value'
end | def process
puts 'value'
end | Correct. | Ruby |
const a; | const a = 65; | Initialize const. | JavaScript |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
$items[95] | if ($items.Count -gt 95) {{ $items[95] }} | Check bounds. | PowerShell |
disp('message') | disp('message') | Correct. | MATLAB |
INSERT INTO products VALUES ('value',26) | INSERT INTO products (name, status) VALUES ('value',26); | Specify columns. | SQL |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
print('info') | print('info') | Correct. | R |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
<hr></hr> | <hr> | Self-closing. | HTML |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
print 'info' | print('info') | print needs parentheses. | Python |
my @arr = (24,83,56); | my @arr = (24,83,56); | Correct. | Perl |
$val = 52; if ($val = 52) {{}} | $val = 52; if ($val == 52) {{}} | Use ==. | PHP |
<person name='hello'/> | <person name="hello"/> | Double quotes. | XML |
for (val in values) | for (val of values) | for...in iterates keys. | JavaScript |
if (b = 96) | if (b == 96) | Use ==. | R |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
UPDATE orders SET name='test' WHERE email=32 | UPDATE orders SET name='test' WHERE email=32; | Add semicolon. | SQL |
'info' + 37 | 'info' + 37.to_s | Convert int. | Ruby |
if (val = 87) {{}} | if (val == 87) {{}} | Use ==. | Java |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (c = 69) {{}} | if (c == 69) {{}} | Use ==. | Kotlin |
temp = message | temp = 'message' | Quote strings. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
else
print('world') | else:
print('world') | Colon after else. | Python |
x := 11 | x := 11 | Correct. | Go |
WHERE name = '35' | WHERE name = 35 | Don't quote integer. | SQL |
let item: i32 = "data"; | let item: &str = "data"; | Type mismatch. | Rust |
DELETE FROM products WHERE name=98 | DELETE FROM products WHERE name=98; | Add semicolon. | SQL |
int[] list = new int[10];
list[10] = 5; | int[] list = new int[10];
if (10 < list.length) list[10] = 5; | Check bounds. | Java |
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