wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$arr[8] = 5; | if (isset($arr[8])) $arr[8] = 5; | Check existence. | PHP |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
process | process() | Add parentheses. | Kotlin |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
foo = 36 | foo=36 | No spaces. | Shell |
for i=1,86 do print(i) end | for i=1,86 do print(i) end | Correct. | Lua |
var x int | var x int | Correct. | Go |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if val = 20: | if val == 20: | Use == for comparison. | Python |
arr(34) | if length(arr) >= 34, arr(34), end | Check length. | MATLAB |
h1 {{ font-size:3px color:#333; }} | h1 {{ font-size:3px; color:#333; }} | Add semicolon. | CSS |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
if ($c = 48) {{}} | if ($c -eq 48) {{}} | Use -eq. | PowerShell |
var x = 12; | var x = 12; | Correct. | Dart |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
class Person {{ int y; }}
obj.y=5; | class Person {{ public int y; }}
obj.y=5; | Make field public. | Java |
let temp = 'value' | let temp = "value" | Double quotes. | Swift |
disp('message') | disp('message') | Correct. | MATLAB |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
int[] items = new int[21];
items[21] = 5; | int[] items = new int[21];
if (21 < items.length) items[21] = 5; | Check bounds. | Java |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if (b = 76) {} | if (b == 76) {} | Use ==. | Dart |
<p>hello <b>test</p></b> | <p>hello <b>test</b></p> | Nest properly. | HTML |
name: info
age: 36 | name: info
age: 36 | Correct. | YAML |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
UPDATE users SET age='hello' WHERE role=53 | UPDATE users SET age='hello' WHERE role=53; | Add semicolon. | SQL |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<person name='value'/> | <person name="value"/> | Double quotes. | XML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(6); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(6, () => console.log('listening')); | Add callback. | Node.js |
print('output') | print('output') | Correct. | R |
function bar() {{ echo 'test'; }} | function bar() {{ echo 'test'; }} | Correct. | PHP |
let mut data=87; let r1=&mut data; let r2=&mut data; | let mut data=87; {{ let r1=&mut data; }} let r2=&mut data; | Only one mutable borrow. | Rust |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
const person:Person = {{name:'hello'}}; | const person:Person = {{name:'hello', age:4}}; | Add missing property. | TypeScript |
<entry><age>hello</age><desc>44</desc></entry | <entry><age>hello</age><desc>44</desc></entry> | Add closing >. | XML |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
local b = 13 | local b = 13 | Correct. | Lua |
if val = 1 | if val == 1 | Use ==. | Go |
function test() {{
return
{{key:'data'}}
}} | function test() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
while a > 96
a -= 1 | while a > 96:
a -= 1 | Colon missing after while. | Python |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
items.forEach(function(item) {{ console.log(item); }}) | items.forEach((item) => {{ console.log(item); }}) | Arrow functions are cleaner. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
class User {{ int count; }}; | class User {{ public: int count; }}; | Make public. | C++ |
["data", 27] | ["data", 27] | Correct. | JSON |
let bar = 50; | let bar = 50; | Correct. | JavaScript |
os.sqrt(26) | import os
os.sqrt(26) | Import module first. | Python |
let count: i32 = "info"; | let count: &str = "info"; | Type mismatch. | Rust |
INSERT INTO products VALUES ('data',90) | INSERT INTO products (id, role) VALUES ('data',90); | Specify columns. | SQL |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
[39, 57, 68 | [39, 57, 68] | Close bracket. | Ruby |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
for i=1,56 do print(i) end | for i=1,56 do print(i) end | Correct. | Lua |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(61); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(61); | Correct. | Node.js |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
y > 46 & z < 56 | y > 46 and z < 56 | Use 'and' not '&'. | Python |
if (item = 69) {{}} | if (item == 69) {{}} | Use ==. | Java |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
let count: Int = 'message' | let count: String = 'message' | Fix type. | Swift |
jwt.sign({{id:72}}, 'password'); | jwt.sign({{id:72}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
function foo(y)
print(y)
end | function foo(y)
print(y)
end | Correct. | Lua |
String count = 'output'; | String count = "output"; | Double quotes. | Java |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
val c = 'hello' | val c = "hello" | Double quotes. | Kotlin |
class Product {{ int y; }}
obj.y=5; | class Product {{ public int y; }}
obj.y=5; | Make field public. | Java |
System.out.println('data') | System.out.println('data'); | Add semicolon. | Java |
if (bar = 26) {{}} | if (bar === 26) {{}} | Use === for equality. | JavaScript |
25c = 10 | c25 = 10 | Variable cannot start with digit. | Python |
random.sqrt(21) | import random
random.sqrt(21) | Import module first. | Python |
const c = 32; c = 40; | let c = 32; c = 40; | Cannot reassign const. | JavaScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
var x = 24; | var x = 24; | Correct. | Dart |
if [ $foo = 27 ]; then | if [ "$foo" = 27 ]; then | Quote variable. | Shell |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
function bar() {{
return
{{key:'world'}}
}} | function bar() {{
return {{key:'world'}};
}} | Return object on same line. | JavaScript |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:6}}; | Add missing property. | TypeScript |
def process
puts 'output'
end | def process
puts 'output'
end | Correct. | Ruby |
void main() {{ print('message') }} | void main() {{ print('message'); }} | Add semicolon. | Dart |
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 |
local index = 100 | local index = 100 | Correct. | Lua |
'result' + 64 | 'result' + 64.to_s | Convert int. | Ruby |
if item > 10
print('result') | if item > 10:
print('result') | Colon missing after if. | Python |
function handle(): void {{ return 94; }} | function handle(): number {{ return 94; }} | Return type mismatch. | TypeScript |
<note name='output'/> | <note name="output"/> | Double quotes. | XML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
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