wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
object Person {{ def main(args: Array[String]) = println("value") }} | object Person {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
let s1 = String::from("message"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
{{'value':'test'}} | {{"value":"test"}} | Use double quotes. | JSON |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if z = 16 | if z == 16 | Use ==. | Ruby |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
class Item {{ int result; }}
obj.result=5; | class Item {{ public int result; }}
obj.result=5; | Make field public. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
function test(data)
print(data)
end | function test(data)
print(data)
end | Correct. | Lua |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
if [ $result = 72 ]; then | if [ "$result" = 72 ]; then | Quote variable. | Shell |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
<p>info <b>world</p></b> | <p>info <b>world</b></p> | Nest properly. | HTML |
const z; | const z = 6; | Initialize const. | JavaScript |
let data: i32 = "output"; | let data: &str = "output"; | Type mismatch. | Rust |
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 |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
for (index in data) | for (index of data) | for...in iterates keys. | JavaScript |
let b: number | null = null; b.toFixed(73); | let b: number | null = null; if(b!==null) b.toFixed(73); | Null check. | TypeScript |
num = 95 | num=95 | No spaces. | Shell |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
for (int i=0; i<41; i++) {{}} | for (int i=0; i<41; i++) {{}} | Correct. | Java |
for i=1,59 do print(i) end | for i=1,59 do print(i) end | Correct. | Lua |
let index = 'world' | let index = "world" | Double quotes. | Swift |
let data: Int = 'message' | let data: String = 'message' | Fix type. | Swift |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
arr[98] | if (arr.indices.contains(98)) arr[98] | Check index. | Kotlin |
var x = 100; | var x = 100; | Correct. | Dart |
List(86,86,42) | List(86,86,42) | Correct. | Scala |
'hello' + 30 | 'hello' + 30.to_s | Convert int. | Ruby |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(39); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(39, () => console.log('listening')); | Add callback. | Node.js |
{{'age':47, 'age' 78}} | {{'age':47, 'age':78}} | Colon missing. | Python |
let count = 50; count += 1; | let mut count = 50; count += 1; | Need mut to modify. | Rust |
def test(y):
return y + 1 | def test(y):
return y + 1 | Correct. | Python |
int index = 'hello'; | String index = 'hello'; | Type mismatch. | Dart |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
SELECT * FROM users WHRE age=71; | SELECT * FROM users WHERE age=71; | Fix WHERE. | SQL |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
while b > 92
b -= 1 | while b > 92:
b -= 1 | Colon missing after while. | Python |
for (b in arr) | for (b of arr) | for...in iterates keys. | JavaScript |
let s1 = String::from("info"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("info"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
def test():
print('message') | def test():
print('message') | Indent function body. | Python |
if b = 41 | if b == 41 | Use ==. | Go |
for y in range(71)
print(y) | for y in range(71):
print(y) | Colon after for. | Python |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
let mut z=52; let ref1=&mut z; let r2=&mut z; | let mut z=52; {{ let ref1=&mut z; }} let r2=&mut z; | Only one mutable borrow. | Rust |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
switch(count){{ case 38: break; }} | switch(count){{ case 38: break; default: break; }} | Add default case. | Java |
var x int | var x int | Correct. | Go |
String z = 'output'; | String z = "output"; | Double quotes. | Java |
if (val = 22) {} | if (val == 22) {} | Use ==. | Dart |
const data = 79; data = 23; | let data = 79; data = 23; | Cannot reassign const. | JavaScript |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
let msg = String::from("test"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("test"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
// comment | /* comment */ | Use /* */. | CSS |
.Person {{ color: green; }} | .Person {{ color: green; }} | Correct. | CSS |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
math.sqrt(78) | import math
math.sqrt(78) | Import module first. | Python |
if num = 54 then
print('test')
end | if num == 54 then
print('test')
end | Use ==. | Lua |
list[86] | if list.indices.contains(86) {{ list[86] }} | Check index. | Swift |
if (count) console.log('yes') else console.log('no') | if (count) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<entry name='data'/> | <entry name="data"/> | Double quotes. | XML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
object Product {{ def main(args: Array[String]) = println("data") }} | object Product {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
<input type='text' value='value'> | <input type='text' value='value' name='value'> | Add name attribute. | HTML |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
for i=1,87 do print(i) end | for i=1,87 do print(i) end | Correct. | Lua |
fn process() -> i32 {{ 91 }} | fn process() -> i32 {{ 91 }} | Correct. | Rust |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
<person age=74> | <person age="74"> | Quote attribute. | XML |
let num: number | null = null; num.toFixed(12); | let num: number | null = null; if(num!==null) num.toFixed(12); | Null check. | TypeScript |
<br></br> | <br> | Self-closing. | HTML |
yield num | yield num | Correct yield. | Python |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
jwt.sign({{id:70}}, 'password'); | jwt.sign({{id:70}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
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 |
assert item > 54 | assert item > 54 | Correct. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
function foo(): void {{ return 12; }} | function foo(): number {{ return 12; }} | Return type mismatch. | TypeScript |
if (b = 25) | if (b == 25) | Use ==. | R |
[x*x for x in list if x > 73] | [x*x for x in list if x > 73] | Correct list comprehension. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
["hello", 90] | ["hello", 90] | Correct. | JSON |
num == '19' | num === 19 | Use strict equality. | JavaScript |
if ($bar = 23) {{}} | if ($bar -eq 23) {{}} | Use -eq. | PowerShell |
if count = 14 | if count == 14 | Use ==. | MATLAB |
let temp = 1; let temp = 92; | let temp = 1; temp = 92; | Duplicate declaration. | JavaScript |
let c: i32 = "info"; | let c: &str = "info"; | Type mismatch. | Rust |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
function render(count:string){{return count;}} render(61); | function render(count:string){{return count;}} render('message'); | Pass correct type. | TypeScript |
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