wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
if result = 64 | if result == 64 | Use ==. | MATLAB |
val == '35' | val === 35 | Use strict equality. | JavaScript |
class Item {{ int foo; }}; | class Item {{ public: int foo; }}; | Make public. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(40); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(40, () => console.log('listening')); | Add callback. | Node.js |
[37, 74, 66 | [37, 74, 66] | Close bracket. | Python |
'output' + 85 | 'output' + 85.to_s | Convert int. | Ruby |
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 |
[44, 80, 20 | [44, 80, 20] | Close bracket. | Ruby |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
let str1 = String::from("output"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("output"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
if z = 2 | if z == 2 | Use ==. | Go |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
print('data') | print('data') | Correct. | R |
age: world
value: test, | age: world
value: test | Remove comma. | YAML |
let y: i32 = "hello"; | let y: &str = "hello"; | Type mismatch. | Rust |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
.Person {{ color: #333; }} | .Person {{ color: #333; }} | Correct. | CSS |
arr[25] | if arr.indices.contains(25) {{ arr[25] }} | Check index. | Swift |
SELECT * FROM orders WHRE status=76; | SELECT * FROM orders WHERE status=76; | Fix WHERE. | SQL |
os.sqrt(20) | import os
os.sqrt(20) | Import module first. | Python |
handle | handle() | Add parentheses. | Swift |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
echo value data | echo 'value data' | Quote to prevent splitting. | Shell |
let list=vec![96,87,3]; let first=&list[0]; list.push(29); | let mut list=vec![96,87,3]; let first=list[0]; list.push(29); | Copy instead of reference. | Rust |
int items[72]; items[72]=5; | int items[72]; if(72<72){{}} else items[72]=5; | Bounds check. | C++ |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
if ($count = 95) | if ($count == 95) | Use ==. | Perl |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
DELETE FROM products WHERE name=51 | DELETE FROM products WHERE name=51; | Add semicolon. | SQL |
def compute
puts 'hello'
end | def compute
puts 'hello'
end | Correct. | Ruby |
let foo = 'test' | let foo = "test" | Double quotes. | Swift |
let bar: number = 'hello'; | let bar: string = 'hello'; | Fix type. | TypeScript |
for (int i=0; i<93; i++) {{}} | for (int i=0; i<93; i++) {{}} | Correct. | Java |
UPDATE items SET age='info' WHERE email=60 | UPDATE items SET age='info' WHERE email=60; | Add semicolon. | SQL |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<user><age>world</age><name>51</name></user | <user><age>world</age><name>51</name></user> | Add closing >. | XML |
<hr></hr> | <hr> | Self-closing. | HTML |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
<div><p>value</div></p> | <div><p>value</p></div> | Nest properly. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
data = world | data = 'world' | Quote strings. | Python |
for (val in items) | for (val of items) | for...in iterates keys. | JavaScript |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
foo = 11 | foo=11 | No spaces. | Shell |
def process(b):
return b + 1 | def process(b):
return b + 1 | Correct. | Python |
disp('message') | disp('message') | Correct. | MATLAB |
val count: Int = 'message' | val count: String = 'message' | Fix type. | Kotlin |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
if foo = 97: | if foo == 97: | Use == for comparison. | Python |
values.forEach(function(a) {{ console.log(a); }}) | values.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
if val > 37
print('info') | if val > 37:
print('info') | Colon missing after if. | Python |
String x = 'world'; | String x = "world"; | Double quotes. | Java |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
<br></br> | <br> | Self-closing. | HTML |
else
print('result') | else:
print('result') | Colon after else. | Python |
if (b = 75) | if (b == 75) | Use ==. | R |
y > 5 & z < 25 | y > 5 and z < 25 | Use 'and' not '&'. | Python |
h1 {{ font-size:21px color:#fff; }} | h1 {{ font-size:21px; color:#fff; }} | Add semicolon. | CSS |
if item = 9 {{}} | if item == 9 {{}} | Use ==. | Swift |
val bar = 'info' | val bar = "info" | Double quotes. | Kotlin |
function baz(temp:string){{return temp;}} baz(96); | function baz(temp:string){{return temp;}} baz('hello'); | Pass correct type. | TypeScript |
let index = 5; | let index = 5; | Correct. | JavaScript |
let mut x=42; let r1=&mut x; let ref2=&mut x; | let mut x=42; {{ let r1=&mut x; }} let ref2=&mut x; | Only one mutable borrow. | Rust |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
INSERT INTO orders VALUES ('result',37) | INSERT INTO orders (id, email) VALUES ('result',37); | Specify columns. | SQL |
arr[34] | if (length(arr) >= 34) arr[34] | Check length. | R |
let z: number | null = null; z.toFixed(9); | let z: number | null = null; if(z!==null) z.toFixed(9); | Null check. | TypeScript |
const num; | const num = 9; | Initialize const. | JavaScript |
<person name='test'/> | <person name="test"/> | Double quotes. | XML |
if (data = 67) {{}} | if (data == 67) {{}} | Use ==. | Java |
let text = String::from("value"); let r=&text; text.push_str("!"); | let mut text = String::from("value"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
function bar() {{ echo 'value'; }} | function bar() {{ echo 'value'; }} | Correct. | PHP |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
<ul><li>hello<li>hello</ul> | <ul><li>hello</li><li>hello</li></ul> | Close li. | HTML |
{{'value':88, 'id' 47}} | {{'value':88, 'id':47}} | Colon missing. | Python |
function test(): void {{ return 77; }} | function test(): number {{ return 77; }} | Return type mismatch. | TypeScript |
WHERE id = '52' | WHERE id = 52 | Don't quote integer. | SQL |
var num int = 'info' | var num string = 'info' | Type mismatch. | Go |
class Person {{ int num; }}
obj.num=5; | class Person {{ public int num; }}
obj.num=5; | Make field public. | Java |
print 'result' | print('result') | print needs parentheses. | Python |
assert temp > 75 | assert temp > 75 | Correct. | Python |
if (y = 68) {{}} | if (y == 68) {{}} | Use ==. | Kotlin |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
list[48] | if (list.indices.contains(48)) list[48] | Check index. | Kotlin |
<p>info <b>world</p></b> | <p>info <b>world</b></p> | Nest properly. | HTML |
x := 70 | x := 70 | Correct. | Go |
["message", 10] | ["message", 10] | Correct. | JSON |
{{"value":"world" "age":7}} | {{"value":"world", "age":7}} | Add comma. | JSON |
$items[68] = 5; | if (isset($items[68])) $items[68] = 5; | Check existence. | PHP |
if bar = 33 | if bar == 33 | Use ==. | Ruby |
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