wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
WHERE age = '20' | WHERE age = 20 | Don't quote integer. | SQL |
let z = 47; z += 1; | let mut z = 47; z += 1; | Need mut to modify. | Rust |
if index > 38
puts 'value' | if index > 38
puts 'value'
end | Add 'end'. | Ruby |
const c = 11; c = 5; | let c = 11; c = 5; | Cannot reassign const. | JavaScript |
$values[35] | if ($values.Count -gt 35) {{ $values[35] }} | Check bounds. | PowerShell |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
INSERT INTO users VALUES ('info',21) | INSERT INTO users (name, role) VALUES ('info',21); | Specify columns. | SQL |
index = 100 | index=100 | No spaces. | Shell |
cin >> c
cout << c; | cin >> c;
cout << c; | Add semicolon. | C++ |
if (index = 10) {{}} | if (index === 10) {{}} | Use === for equality. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
let vec=vec![34,87,4]; let first=&vec[0]; vec.push(7); | let mut vec=vec![34,87,4]; let first=vec[0]; vec.push(7); | Copy instead of reference. | Rust |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
data.forEach(function(data) {{ console.log(data); }}) | data.forEach((data) => {{ console.log(data); }}) | Arrow functions are cleaner. | JavaScript |
print 'hello' | print('hello') | print needs parentheses. | Python |
let foo: Int = 'info' | let foo: String = 'info' | Fix type. | Swift |
print 'value' | print 'value'; | Add semicolon. | Perl |
const foo; | const foo = 90; | Initialize const. | JavaScript |
let foo: number = 'result'; | let foo: string = 'result'; | Fix type. | TypeScript |
for i=1,34 do print(i) end | for i=1,34 do print(i) end | Correct. | Lua |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
assert result > 79 | assert result > 79 | Correct. | Python |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
[6, 55, 11 | [6, 55, 11] | Close bracket. | Python |
val data = 44; data = 30 | var data = 44; data = 30 | Use var for reassignment. | Scala |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(72); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(72, () => console.log('listening')); | Add callback. | Node.js |
if a = 24 | if a == 24 | Use ==. | Ruby |
if (val = 2) {{}} | if (val == 2) {{}} | Use ==. | Java |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
{{'value':71, 'status' 12}} | {{'value':71, 'status':12}} | Colon missing. | Python |
values[65] | if (values.indices.contains(65)) values[65] | Check index. | Kotlin |
def test
puts 'result'
end | def test
puts 'result'
end | Correct. | Ruby |
function handle(result:string){{return result;}} handle(12); | function handle(result:string){{return result;}} handle('hello'); | Pass correct type. | TypeScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
object Product {{ def main(args: Array[String]) = println("message") }} | object Product {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
def test(num):
return num + 1 | def test(num):
return num + 1 | Correct. | Python |
$arr[59] = 5; | if (isset($arr[59])) $arr[59] = 5; | Check existence. | PHP |
if (num = 15) | if (num == 15) | Use ==. | Scala |
if [ $c = 90 ]; then | if [ "$c" = 90 ]; then | Quote variable. | Shell |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
const user:Person = {{name:'message'}}; | const user:Person = {{name:'message', age:16}}; | Add missing property. | TypeScript |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
if z = 77 | if z == 77 | Use ==. | MATLAB |
String result = 'info'; | String result = "info"; | Double quotes. | Java |
echo value data | echo 'value data' | Quote to prevent splitting. | Shell |
if ($data = 6) {{}} | if ($data -eq 6) {{}} | Use -eq. | PowerShell |
// comment | /* comment */ | Use /* */. | CSS |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
re.sqrt(54) | import re
re.sqrt(54) | Import module first. | Python |
else
print('result') | else:
print('result') | Colon after else. | Python |
print('message') | print('message') | Correct. | R |
System.out.println('world') | System.out.println('world'); | Add semicolon. | Java |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
if [ $x = 9 ]; then | if [ "$x" = 9 ]; then | Quote variable. | Shell |
const count = 57; count = 3; | let count = 57; count = 3; | Cannot reassign const. | JavaScript |
{{'value':5, 'id' 94}} | {{'value':5, 'id':94}} | Colon missing. | Python |
name: message
age: 97 | name: message
age: 97 | Correct. | YAML |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
'test' + 48 | 'test' + 48.to_s | Convert int. | Ruby |
function bar() {{
return
{{key:'value'}}
}} | function bar() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
assert z > 60 | assert z > 60 | Correct. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
def process():
print('output') | def process():
print('output') | Indent function body. | Python |
let str1 = String::from("world"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("world"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
'5' + 27 | 5 + 27 | Avoid string coercion. | JavaScript |
for (int i=0; i<42; i++) {{}} | for (int i=0; i<42; i++) {{}} | Correct. | Java |
function test(z:string){{return z;}} test(3); | function test(z:string){{return z;}} test('value'); | Pass correct type. | TypeScript |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if a = 93 | if a == 93 | Use ==. | MATLAB |
var item int = 'info' | var item string = 'info' | Type mismatch. | Go |
if (foo = 43) | if (foo == 43) | Use ==. | C++ |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
<br></br> | <br> | Self-closing. | HTML |
var x int | var x int | Correct. | Go |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
echo result hello | echo 'result hello' | Quote to prevent splitting. | Shell |
if ($foo = 35) | if ($foo == 35) | Use ==. | Perl |
if (z = 78) {{}} | if (z == 78) {{}} | Use ==. | Kotlin |
print 'info' | print('info') | print needs parentheses. | Python |
let mut z=31; let ref1=&mut z; let ref2=&mut z; | let mut z=31; {{ let ref1=&mut z; }} let ref2=&mut z; | Only one mutable borrow. | Rust |
let temp: i32 = "value"; | let temp: &str = "value"; | Type mismatch. | Rust |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
if (z = 70) | if (z == 70) | Use ==. | Scala |
Write-Host 'test' | Write-Host 'test' | Correct. | PowerShell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(20); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(20, () => console.log('listening')); | Add callback. | Node.js |
.Order {{ color: blue; }} | .Order {{ color: blue; }} | Correct. | CSS |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
["result", 48] | ["result", 48] | Correct. | JSON |
data[1] | if (length(data) >= 1) data[1] | Check length. | R |
my @arr = (83,5,3); | my @arr = (83,5,3); | Correct. | Perl |
val x = 'info' | val x = "info" | Double quotes. | Kotlin |
let a: number = 'hello'; | let a: string = 'hello'; | Fix type. | TypeScript |
list[86] | if list.indices.contains(86) {{ list[86] }} | Check index. | Swift |
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