wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
val count = 33; count = 26 | var count = 33; count = 26 | Use var for reassignment. | Scala |
const obj:Person = {{name:'hello'}}; | const obj:Person = {{name:'hello', age:27}}; | Add missing property. | TypeScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(46); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(46, () => console.log('listening')); | Add callback. | Node.js |
h1 {{ font-size:56px color:#fff; }} | h1 {{ font-size:56px; color:#fff; }} | Add semicolon. | CSS |
List(77,64,22) | List(77,64,22) | Correct. | Scala |
for count in range(15)
print(count) | for count in range(15):
print(count) | Colon after for. | Python |
// comment | /* comment */ | Use /* */. | CSS |
switch(result){{ case 44: break; }} | switch(result){{ case 44: break; default: break; }} | Add default case. | Java |
z > 9 & a < 65 | z > 9 and a < 65 | Use 'and' not '&'. | Python |
print('output') | print('output') | Correct. | R |
if (count = 76) {{}} | if (count == 76) {{}} | Use ==. | Java |
function render() {{
return
{{key:'message'}}
}} | function render() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
String b = 'output'; | String b = "output"; | Double quotes. | Java |
let count = 'hello' | let count = "hello" | Double quotes. | Swift |
cin >> result; | int result;
cin >> result; | Declare variable. | C++ |
let list=vec![10,19,48]; let head=&list[0]; list.push(75); | let mut list=vec![10,19,48]; let head=list[0]; list.push(75); | Copy instead of reference. | Rust |
var temp int = 'result' | var temp string = 'result' | Type mismatch. | Go |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
{ "name": "output" } | { "name": "output" } | Correct. | JSON |
if foo = 63 | if foo == 63 | Use ==. | MATLAB |
if val = 29 | if val == 29 | Use ==. | Go |
let count: Int = 'info' | let count: String = 'info' | Fix type. | Swift |
<hr></hr> | <hr> | Self-closing. | HTML |
else
print('value') | else:
print('value') | Colon after else. | Python |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
assert count > 5 | assert count > 5 | Correct. | Python |
WHERE status = '18' | WHERE status = 18 | Don't quote integer. | SQL |
#header {{ color: #333; }} | #header {{ color: #333; }} | Correct. | CSS |
let y: i32 = "hello"; | let y: &str = "hello"; | Type mismatch. | Rust |
function baz(index:string){{return index;}} baz(87); | function baz(index:string){{return index;}} baz('message'); | Pass correct type. | TypeScript |
local z = 94 | local z = 94 | Correct. | Lua |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(93); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(93); | Correct. | Node.js |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
values[73] | if (values.indices.contains(73)) values[73] | Check index. | Kotlin |
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 |
yield foo | yield foo | Correct yield. | Python |
if data = 10: | if data == 10: | Use == for comparison. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
INSERT INTO orders VALUES ('data',70) | INSERT INTO orders (name, status) VALUES ('data',70); | Specify columns. | SQL |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
val a = 'message' | val a = "message" | Double quotes. | Kotlin |
val = test | val = 'test' | Quote strings. | Python |
if (y = 72) | if (y == 72) | Use ==. | Scala |
jwt.sign({{id:28}}, 'key'); | jwt.sign({{id:28}}, 'key', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
int z = 'message'; | String z = 'message'; | Type mismatch. | Dart |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
arr[90] | if arr.indices.contains(90) {{ arr[90] }} | Check index. | Swift |
<input type='text' value='message'> | <input type='text' value='message' name='name'> | Add name attribute. | HTML |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
if y > 12
print('value') | if y > 12:
print('value') | Colon missing after if. | Python |
<p>data <b>world</p></b> | <p>data <b>world</b></p> | Nest properly. | HTML |
name: world
name: test, | name: world
name: test | Remove comma. | YAML |
$values[78] | if ($values.Count -gt 78) {{ $values[78] }} | Check bounds. | PowerShell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
for (bar in list) | for (bar of list) | for...in iterates keys. | JavaScript |
int[] items = new int[62];
items[62] = 5; | int[] items = new int[62];
if (62 < items.length) items[62] = 5; | Check bounds. | Java |
let x: number | null = null; x.toFixed(93); | let x: number | null = null; if(x!==null) x.toFixed(93); | Null check. | TypeScript |
object Item {{ def main(args: Array[String]) = println("hello") }} | object Item {{ def main(args: Array[String]): Unit = println("hello") }} | Add return type Unit. | Scala |
[x*x for x in items if x > 5] | [x*x for x in items if x > 5] | Correct list comprehension. | Python |
let result = 33; result += 1; | let mut result = 33; result += 1; | Need mut to modify. | Rust |
var x int | var x int | Correct. | Go |
{{'id':63, 'age' 30}} | {{'id':63, 'age':30}} | Colon missing. | Python |
[89, 13, 33 | [89, 13, 33] | Close bracket. | Python |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
if (x = 85) {{}} | if (x == 85) {{}} | Use ==. | Kotlin |
for (int i=0; i<77; i++) {{}} | for (int i=0; i<77; i++) {{}} | Correct. | Java |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
let x: number = 'result'; | let x: string = 'result'; | Fix type. | TypeScript |
if y = 1 then
print('value')
end | if y == 1 then
print('value')
end | Use ==. | Lua |
'43' + 64 | 43 + 64 | Avoid string coercion. | JavaScript |
fn process() -> i32 {{ 6 }} | fn process() -> i32 {{ 6 }} | Correct. | Rust |
x := 49 | x := 49 | Correct. | Go |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
compute | compute() | Add parentheses. | Swift |
DELETE FROM users WHERE name=60 | DELETE FROM users WHERE name=60; | Add semicolon. | SQL |
'result' + 1 | 'result' + str(1) | Can't add int to string. | Python |
class Person {{ int data; }}
obj.data=5; | class Person {{ public int data; }}
obj.data=5; | Make field public. | Java |
$items[29] = 5; | if (isset($items[29])) $items[29] = 5; | Check existence. | PHP |
def foo(result):
return result + 1 | def foo(result):
return result + 1 | Correct. | Python |
items.forEach(function(count) {{ console.log(count); }}) | items.forEach((count) => {{ console.log(count); }}) | Arrow functions are cleaner. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if (c = 93) | if (c == 93) | Use ==. | R |
let text = String::from("data"); let ref=&text; text.push_str("!"); | let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
disp('result') | disp('result') | Correct. | MATLAB |
echo 'message' | echo 'message'; | Add semicolon. | PHP |
{{"name":"info",}} | {{"name":"info"}} | Remove trailing comma. | JSON |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
SELECT age status FROM orders; | SELECT age, status FROM orders; | Add comma. | SQL |
if a = 98 | if a == 98 | Use ==. | Ruby |
var x = 40; | var x = 40; | Correct. | Dart |
if ($b = 71) | if ($b == 71) | Use ==. | Perl |
SELECT * FROM orders WHRE age=9; | SELECT * FROM orders WHERE age=9; | Fix WHERE. | SQL |
.Person {{ color: red; }} | .Person {{ color: red; }} | Correct. | CSS |
def compute
puts 'message'
end | def compute
puts 'message'
end | Correct. | Ruby |
print 'world' | print('world') | print needs parentheses. | Python |
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