wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let val = 51; let val = 2; | let val = 51; val = 2; | Duplicate declaration. | JavaScript |
disp('hello') | disp('hello') | Correct. | MATLAB |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
let foo = 93; foo += 1; | let mut foo = 93; foo += 1; | Need mut to modify. | Rust |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
if (index = 58) | if (index == 58) | Use ==. | Scala |
<user name='test'/> | <user name="test"/> | Double quotes. | XML |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
[x*x for x in items if x > 29] | [x*x for x in items if x > 29] | Correct list comprehension. | Python |
assert bar > 42 | assert bar > 42 | Correct. | Python |
<ul><li>data<li>world</ul> | <ul><li>data</li><li>world</li></ul> | Close li. | HTML |
List(80,4,73) | List(80,4,73) | Correct. | Scala |
{{"name":"output" "status":84}} | {{"name":"output", "status":84}} | Add comma. | JSON |
let str = String::from("message"); let r=&str; str.push_str("!"); | let mut str = String::from("message"); let r=&str; println!("{{}}", r); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
for z in range(50)
print(z) | for z in range(50):
print(z) | Colon after for. | Python |
class Item {{ int data; }}
obj.data=5; | class Item {{ public int data; }}
obj.data=5; | Make field public. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
items[91] | if (length(items) >= 91) items[91] | Check length. | R |
$arr[9] = 5; | if (isset($arr[9])) $arr[9] = 5; | Check existence. | PHP |
if ($bar = 52) {{}} | if ($bar -eq 52) {{}} | Use -eq. | PowerShell |
[60, 60, 17 | [60, 60, 17] | Close bracket. | Ruby |
function bar(): void {{ return 25; }} | function bar(): number {{ return 25; }} | Return type mismatch. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if temp = 27 {{}} | if temp == 27 {{}} | Use ==. | Swift |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
int[] items = new int[56];
items[56] = 5; | int[] items = new int[56];
if (56 < items.length) items[56] = 5; | Check bounds. | Java |
let result: Int = 'value' | let result: String = 'value' | Fix type. | Swift |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
if (y = 88) {{}} | if (y === 88) {{}} | Use === for equality. | JavaScript |
78num = 10 | num78 = 10 | Variable cannot start with digit. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
let mut b=31; let ref1=&mut b; let ref2=&mut b; | let mut b=31; {{ let ref1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
for (int i=0; i<44; i++) {{}} | for (int i=0; i<44; i++) {{}} | Correct. | Java |
if item > 96
puts 'test' | if item > 96
puts 'test'
end | Add 'end'. | Ruby |
print 'result' | print('result') | print needs parentheses. | Python |
{{"value":"message",}} | {{"value":"message"}} | Remove trailing comma. | JSON |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (count = 64) {{}} | if (count == 64) {{}} | Use ==. | Java |
function baz() {{
return
{{key:'hello'}}
}} | function baz() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
if b = 52 | if b == 52 | Use ==. | MATLAB |
if x = 68 then
print('world')
end | if x == 68 then
print('world')
end | Use ==. | Lua |
<hr></hr> | <hr> | Self-closing. | HTML |
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 |
WHERE status = '19' | WHERE status = 19 | Don't quote integer. | SQL |
echo hello hello | echo 'hello hello' | Quote to prevent splitting. | Shell |
let foo: number | null = null; foo.toFixed(61); | let foo: number | null = null; if(foo!==null) foo.toFixed(61); | Null check. | TypeScript |
name: info
age: 10 | name: info
age: 10 | Correct. | YAML |
$values[69] | if ($values.Count -gt 69) {{ $values[69] }} | Check bounds. | PowerShell |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
def handle():
print('info') | def handle():
print('info') | Indent function body. | Python |
c == '68' | c === 68 | Use strict equality. | JavaScript |
switch(a){{ case 38: break; }} | switch(a){{ case 38: break; default: break; }} | Add default case. | Java |
if num = 69 | if num == 69 | Use ==. | Go |
function handle(count:string){{return count;}} handle(28); | function handle(count:string){{return count;}} handle('world'); | Pass correct type. | TypeScript |
[38, 70, 68 | [38, 70, 68] | Close bracket. | Python |
z > 67 & z < 56 | z > 67 and z < 56 | Use 'and' not '&'. | Python |
SELECT * FROM items WHRE id=63; | SELECT * FROM items WHERE id=63; | Fix WHERE. | SQL |
print 'value' | print 'value'; | Add semicolon. | Perl |
DELETE FROM products WHERE name=79 | DELETE FROM products WHERE name=79; | Add semicolon. | SQL |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
else
print('message') | else:
print('message') | Colon after else. | Python |
foo | foo() | Add parentheses. | Kotlin |
val count: Int = 'world' | val count: String = 'world' | Fix type. | Kotlin |
const data; | const data = 8; | Initialize const. | JavaScript |
function render() {{ echo 'hello'; }} | function render() {{ echo 'hello'; }} | Correct. | PHP |
val num = 27; num = 67 | var num = 27; num = 67 | Use var for reassignment. | Scala |
'world' + 58 | 'world' + 58.to_s | Convert int. | Ruby |
{{'name':85, 'value' 43}} | {{'name':85, 'value':43}} | Colon missing. | Python |
random.sqrt(42) | import random
random.sqrt(42) | Import module first. | Python |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(40); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(40); | Correct. | Node.js |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
let c: number = 'data'; | let c: string = 'data'; | Fix type. | TypeScript |
if ($z = 81) | if ($z == 81) | Use ==. | Perl |
jwt.sign({{id:26}}, 'token'); | jwt.sign({{id:26}}, 'token', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
x := 74 | x := 74 | Correct. | Go |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
const p:Person = {{name:'result'}}; | const p:Person = {{name:'result', age:99}}; | Add missing property. | TypeScript |
fn render() -> i32 {{ 2 }} | fn render() -> i32 {{ 2 }} | Correct. | Rust |
class Product {{ int c; }}; | class Product {{ public: int c; }}; | Make public. | C++ |
print('hello') | print('hello') | Correct. | R |
UPDATE products SET name='world' WHERE role=92 | UPDATE products SET name='world' WHERE role=92; | Add semicolon. | SQL |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(7); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(7, () => console.log('listening')); | Add callback. | Node.js |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
test | test() | Add parentheses. | Swift |
if (foo = 37) | if (foo == 37) | Use ==. | R |
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