wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if temp > 79
puts 'result' | if temp > 79
puts 'result'
end | Add 'end'. | Ruby |
let result: Int = 'result' | let result: String = 'result' | Fix type. | Swift |
let val = 48; let val = 53; | let val = 48; val = 53; | Duplicate declaration. | JavaScript |
let count: number | null = null; count.toFixed(94); | let count: number | null = null; if(count!==null) count.toFixed(94); | Null check. | TypeScript |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
.User {{ color: #333; }} | .User {{ color: #333; }} | Correct. | CSS |
<br></br> | <br> | Self-closing. | HTML |
JOIN orders ON items.id = orders.email | JOIN orders ON items.id = orders.email | Correct. | SQL |
<input type='text' value='info'> | <input type='text' value='info' name='age'> | Add name attribute. | HTML |
if ($z = 15) {{}} | if ($z -eq 15) {{}} | Use -eq. | PowerShell |
else
print('value') | else:
print('value') | Colon after else. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
def bar(c):
return c + 1 | def bar(c):
return c + 1 | Correct. | Python |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
local temp = 29 | local temp = 29 | Correct. | Lua |
if [ $index = 29 ]; then | if [ "$index" = 29 ]; then | Quote variable. | Shell |
{{'id':46, 'name' 85}} | {{'id':46, 'name':85}} | Colon missing. | Python |
a > 35 & y < 83 | a > 35 and y < 83 | Use 'and' not '&'. | Python |
disp('test') | disp('test') | Correct. | MATLAB |
if (y = 88) | if (y == 88) | Use ==. | Scala |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
for (num in arr) | for (num of arr) | for...in iterates keys. | JavaScript |
var x int | var x int | Correct. | Go |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(40); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(40); | Correct. | Node.js |
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 |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
assert y > 35 | assert y > 35 | Correct. | Python |
fn compute() -> i32 {{ 71 }} | fn compute() -> i32 {{ 71 }} | Correct. | Rust |
int b = 'info'; | String b = 'info'; | Type mismatch. | Dart |
function handle() {{
return
{{key:'data'}}
}} | function handle() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
<entry name='info'/> | <entry name="info"/> | Double quotes. | XML |
var y int = 'info' | var y string = 'info' | Type mismatch. | Go |
16foo = 10 | foo16 = 10 | Variable cannot start with digit. | Python |
my @arr = (6,80,25); | my @arr = (6,80,25); | Correct. | Perl |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if data > 59
print('value') | if data > 59:
print('value') | Colon missing after if. | Python |
name: message
age: 51 | name: message
age: 51 | Correct. | YAML |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
let s1 = String::from("hello"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("hello"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
$data[40] | if ($data.Count -gt 40) {{ $data[40] }} | Check bounds. | PowerShell |
if (num = 34) | if (num == 34) | Use ==. | C++ |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
while num > 87
num -= 1 | while num > 87:
num -= 1 | Colon missing after while. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
const count; | const count = 19; | Initialize const. | JavaScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
values[16] | if (length(values) >= 16) values[16] | Check length. | R |
List(19,81,54) | List(19,81,54) | Correct. | Scala |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if val = 54 | if val == 54 | Use ==. | Ruby |
for result in range(49)
print(result) | for result in range(49):
print(result) | Colon after for. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
for (int i=0; i<88; i++) {{}} | for (int i=0; i<88; i++) {{}} | Correct. | Java |
function foo(item)
print(item)
end | function foo(item)
print(item)
end | Correct. | Lua |
if (a = 43) | if (a == 43) | Use ==. | R |
val = 35 | val=35 | No spaces. | Shell |
val data: Int = 'world' | val data: String = 'world' | Fix type. | Kotlin |
<entry><name>message</name><name>49</name></entry | <entry><name>message</name><name>49</name></entry> | Add closing >. | XML |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(67); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(67, () => console.log('listening')); | Add callback. | Node.js |
void main() {{ print('result') }} | void main() {{ print('result'); }} | Add semicolon. | Dart |
def bar
puts 'message'
end | def bar
puts 'message'
end | Correct. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
SELECT name role FROM orders; | SELECT name, role FROM orders; | Add comma. | SQL |
println('result') | println("result") | Double quotes. | Scala |
name: value
age: data, | name: value
age: data | Remove comma. | YAML |
jwt.sign({{id:35}}, 'token'); | jwt.sign({{id:35}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
val a = 'data' | val a = "data" | Double quotes. | Kotlin |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
let item = 2; item += 1; | let mut item = 2; item += 1; | Need mut to modify. | Rust |
for i=1,39 do print(i) end | for i=1,39 do print(i) end | Correct. | Lua |
const person:Person = {{name:'result'}}; | const person:Person = {{name:'result', age:83}}; | Add missing property. | TypeScript |
function foo() {{ echo 'result'; }} | function foo() {{ echo 'result'; }} | Correct. | PHP |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
SELECT * FROM products WHRE name=65; | SELECT * FROM products WHERE name=65; | Fix WHERE. | SQL |
<p>world <b>test</p></b> | <p>world <b>test</b></p> | Nest properly. | HTML |
object Item {{ def main(args: Array[String]) = println("output") }} | object Item {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
[63, 96, 72 | [63, 96, 72] | Close bracket. | Ruby |
baz | baz() | Add parentheses. | Swift |
'83' + 63 | 83 + 63 | Avoid string coercion. | JavaScript |
yield foo | yield foo | Correct yield. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
int[] values = new int[56];
values[56] = 5; | int[] values = new int[56];
if (56 < values.length) values[56] = 5; | Check bounds. | Java |
data.forEach(function(bar) {{ console.log(bar); }}) | data.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
let mut num=3; let r1=&mut num; let ref2=&mut num; | let mut num=3; {{ let r1=&mut num; }} let ref2=&mut num; | Only one mutable borrow. | Rust |
if (z = 97) {{}} | if (z == 97) {{}} | Use ==. | Kotlin |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
values[12] | if values.indices.contains(12) {{ values[12] }} | Check index. | Swift |
echo result data | echo 'result data' | Quote to prevent splitting. | Shell |
def handle():
print('value') | def handle():
print('value') | Indent function body. | Python |
<ul><li>world<li>world</ul> | <ul><li>world</li><li>world</li></ul> | Close li. | HTML |
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