wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
jwt.sign({{id:63}}, 'password'); | jwt.sign({{id:63}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
{{'id':32, 'value' 3}} | {{'id':32, 'value':3}} | Colon missing. | Python |
$items[95] = 5; | if (isset($items[95])) $items[95] = 5; | Check existence. | PHP |
<input type='text' value='world'> | <input type='text' value='world' name='status'> | Add name attribute. | HTML |
echo test data | echo 'test data' | Quote to prevent splitting. | Shell |
SELECT age email FROM products; | SELECT age, email FROM products; | Add comma. | SQL |
System.out.println('world') | System.out.println('world'); | Add semicolon. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
function test() {{
return
{{key:'hello'}}
}} | function test() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
.Product {{ color: #fff; }} | .Product {{ color: #fff; }} | Correct. | CSS |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
SELECT * FROM users WHRE age=60; | SELECT * FROM users WHERE age=60; | Fix WHERE. | SQL |
<br></br> | <br> | Self-closing. | HTML |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(95); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(95, () => console.log('listening')); | Add callback. | Node.js |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
print 'output' | print 'output'; | Add semicolon. | Perl |
val == '18' | val === 18 | Use strict equality. | JavaScript |
if c = 96 | if c == 96 | Use ==. | Ruby |
var x = 45; | var x = 45; | Correct. | Dart |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<hr></hr> | <hr> | Self-closing. | HTML |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
x := 50 | x := 50 | Correct. | Go |
int items[100]; items[100]=5; | int items[100]; if(100<100){{}} else items[100]=5; | Bounds check. | C++ |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
{{"id":"message" "status":63}} | {{"id":"message", "status":63}} | Add comma. | JSON |
print('value') | print('value') | Correct. | R |
int result = 'result'; | String result = 'result'; | Type mismatch. | Dart |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
$index = 67; if ($index = 67) {{}} | $index = 67; if ($index == 67) {{}} | Use ==. | PHP |
let mut y=80; let ref1=&mut y; let ref2=&mut y; | let mut y=80; {{ let ref1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
if val = 35: | if val == 35: | Use == for comparison. | Python |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let b: number | null = null; b.toFixed(72); | let b: number | null = null; if(b!==null) b.toFixed(72); | Null check. | TypeScript |
for i=1,78 do print(i) end | for i=1,78 do print(i) end | Correct. | Lua |
val b: Int = 'result' | val b: String = 'result' | Fix type. | Kotlin |
raise 'message' | raise Exception('message') | Raise needs an exception class. | Python |
var x int | var x int | Correct. | Go |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
my @arr = (77,92,81); | my @arr = (77,92,81); | Correct. | Perl |
{{"value":"hello",}} | {{"value":"hello"}} | Remove trailing comma. | JSON |
JOIN products ON products.id = products.age | JOIN products ON products.id = products.age | Correct. | SQL |
function bar(a)
print(a)
end | function bar(a)
print(a)
end | Correct. | Lua |
<ul><li>test<li>data</ul> | <ul><li>test</li><li>data</li></ul> | Close li. | HTML |
WHERE age = '63' | WHERE age = 63 | Don't quote integer. | SQL |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let result = 75; | let result = 75; | Correct. | JavaScript |
items.forEach(function(y) {{ console.log(y); }}) | items.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
fn process() -> i32 {{ 29 }} | fn process() -> i32 {{ 29 }} | Correct. | Rust |
for (int i=0; i<3; i++) {{}} | for (int i=0; i<3; i++) {{}} | Correct. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(90); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(90); | Correct. | Node.js |
def handle(b):
return b + 1 | def handle(b):
return b + 1 | Correct. | Python |
#content {{ color: red; }} | #content {{ color: red; }} | Correct. | CSS |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
if bar > 51
print('info') | if bar > 51:
print('info') | Colon missing after if. | Python |
for val in range(93)
print(val) | for val in range(93):
print(val) | Colon after for. | Python |
<p>result <b>data</p></b> | <p>result <b>data</b></p> | Nest properly. | HTML |
if (bar) console.log('yes') else console.log('no') | if (bar) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
list[23] | if (length(list) >= 23) list[23] | Check length. | R |
local z = 10 | local z = 10 | Correct. | Lua |
if index = 15 {{}} | if index == 15 {{}} | Use ==. | Swift |
const person:Person = {{name:'test'}}; | const person:Person = {{name:'test', age:45}}; | Add missing property. | TypeScript |
[95, 62, 90 | [95, 62, 90] | Close bracket. | Python |
DELETE FROM products WHERE status=7 | DELETE FROM products WHERE status=7; | Add semicolon. | SQL |
Write-Host 'result' | Write-Host 'result' | Correct. | PowerShell |
[x*x for x in arr if x > 1] | [x*x for x in arr if x > 1] | Correct list comprehension. | Python |
INSERT INTO items VALUES ('data',29) | INSERT INTO items (name, status) VALUES ('data',29); | Specify columns. | SQL |
int[] values = new int[20];
values[20] = 5; | int[] values = new int[20];
if (20 < values.length) values[20] = 5; | Check bounds. | Java |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
if num = 27 | if num == 27 | Use ==. | MATLAB |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
class Person {{ int count; }}
obj.count=5; | class Person {{ public int count; }}
obj.count=5; | Make field public. | Java |
let val: number | null = null; val.toFixed(4); | let val: number | null = null; if(val!==null) val.toFixed(4); | Null check. | TypeScript |
<person age=39> | <person age="39"> | Quote attribute. | XML |
h1 {{ font-size:77px color:green; }} | h1 {{ font-size:77px; color:green; }} | Add semicolon. | CSS |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
.Item {{ color: #fff; }} | .Item {{ color: #fff; }} | Correct. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
if x = 64 | if x == 64 | Use ==. | Go |
println('test') | println("test") | Double quotes. | Scala |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
for (int i=0; i<15; i++) {{}} | for (int i=0; i<15; i++) {{}} | Correct. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if [ $foo = 49 ]; then | if [ "$foo" = 49 ]; then | Quote variable. | Shell |
if (result = 20) | if (result == 20) | Use ==. | C++ |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
fmt.Println 'world' | fmt.Println('world') | Missing parentheses. | Go |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(42); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('result')); app.listen(42, () => console.log('listening')); | Add callback. | Node.js |
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