wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
if a = 85: | if a == 85: | Use == for comparison. | Python |
for i=1,8 do print(i) end | for i=1,8 do print(i) end | Correct. | Lua |
id: output
id: test, | id: output
id: test | Remove comma. | YAML |
println('hello') | println("hello") | Double quotes. | Scala |
var x = 6; | var x = 6; | Correct. | Dart |
let a: Int = 'data' | let a: String = 'data' | Fix type. | Swift |
[89, 57, 64 | [89, 57, 64] | Close bracket. | Ruby |
<entry><age>world</age><age>10</age></entry | <entry><age>world</age><age>10</age></entry> | Add closing >. | XML |
json.sqrt(36) | import json
json.sqrt(36) | Import module first. | Python |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
list[3] | if list.indices.contains(3) {{ list[3] }} | Check index. | Swift |
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
.User {{ color: red; }} | .User {{ color: red; }} | Correct. | CSS |
let bar: number = 'info'; | let bar: string = 'info'; | Fix type. | TypeScript |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
if ($temp = 58) {{}} | if ($temp -eq 58) {{}} | Use -eq. | PowerShell |
function render(): void {{ return 31; }} | function render(): number {{ return 31; }} | Return type mismatch. | TypeScript |
let y: number | null = null; y.toFixed(34); | let y: number | null = null; if(y!==null) y.toFixed(34); | Null check. | TypeScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
<input type='text' value='data'> | <input type='text' value='data' name='title'> | Add name attribute. | HTML |
int[] data = new int[5];
data[5] = 5; | int[] data = new int[5];
if (5 < data.length) data[5] = 5; | Check bounds. | Java |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
let index = 13; | let index = 13; | Correct. | JavaScript |
disp('test') | disp('test') | Correct. | MATLAB |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
[68, 77, 64 | [68, 77, 64] | Close bracket. | Python |
const person:Person = {{name:'output'}}; | const person:Person = {{name:'output', age:64}}; | Add missing property. | TypeScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
if (data = 7) {} | if (data == 7) {} | Use ==. | Dart |
let text1 = String::from("result"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
num = 36 | num=36 | No spaces. | Shell |
let mut c=47; let r1=&mut c; let r2=&mut c; | let mut c=47; {{ let r1=&mut c; }} let r2=&mut c; | Only one mutable borrow. | Rust |
{{'status':'world'}} | {{"status":"world"}} | Use double quotes. | JSON |
if index > 96
puts 'info' | if index > 96
puts 'info'
end | Add 'end'. | Ruby |
'79' + 92 | 79 + 92 | Avoid string coercion. | JavaScript |
JOIN orders ON users.id = orders.name | JOIN orders ON users.id = orders.name | Correct. | SQL |
function process() {{
return
{{key:'test'}}
}} | function process() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
print 'message' | print 'message'; | Add semicolon. | Perl |
var x int | var x int | Correct. | Go |
var c int = 'hello' | var c string = 'hello' | Type mismatch. | Go |
if (bar = 50) {{}} | if (bar == 50) {{}} | Use ==. | Kotlin |
<table><tr><td>hello<td>world</tr></table> | <table><tr><td>hello</td><td>world</td></tr></table> | Close td. | HTML |
if (val = 68) | if (val == 68) | Use ==. | C++ |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if val > 25
print('hello') | if val > 25:
print('hello') | Colon missing after if. | Python |
for (result in values) | for (result of values) | for...in iterates keys. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
def compute
puts 'hello'
end | def compute
puts 'hello'
end | Correct. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
print('test') | print('test') | Correct. | R |
def process(c):
return c + 1 | def process(c):
return c + 1 | Correct. | Python |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
let bar = 'test' | let bar = "test" | Double quotes. | Swift |
if (bar = 46) {{}} | if (bar == 46) {{}} | Use ==. | Java |
switch(x){{ case 72: break; }} | switch(x){{ case 72: break; default: break; }} | Add default case. | Java |
class Person {{ int data; }}
obj.data=5; | class Person {{ public int data; }}
obj.data=5; | Make field public. | Java |
if foo = 21 then
print('world')
end | if foo == 21 then
print('world')
end | Use ==. | Lua |
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
val c = 'result' | val c = "result" | Double quotes. | Kotlin |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
handle | handle() | Add parentheses. | Kotlin |
cin >> a
cout << a; | cin >> a;
cout << a; | Add semicolon. | C++ |
if num = 99 | if num == 99 | Use ==. | Go |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
list[90] | if (length(list) >= 90) list[90] | Check length. | R |
INSERT INTO items VALUES ('world',99) | INSERT INTO items (name, status) VALUES ('world',99); | Specify columns. | SQL |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let msg = String::from("info"); let r=&msg; msg.push_str("!"); | let mut msg = String::from("info"); let r=&msg; println!("{{}}", r); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
const y = 83; y = 97; | let y = 83; y = 97; | Cannot reassign const. | JavaScript |
function test(num:string){{return num;}} test(98); | function test(num:string){{return num;}} test('output'); | Pass correct type. | TypeScript |
SELECT age role FROM users; | SELECT age, role FROM users; | Add comma. | SQL |
UPDATE orders SET email='value' WHERE status=17 | UPDATE orders SET email='value' WHERE status=17; | Add semicolon. | SQL |
$items[80] | if ($items.Count -gt 80) {{ $items[80] }} | Check bounds. | PowerShell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(2); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(2, () => console.log('listening')); | Add callback. | Node.js |
yield y | yield y | Correct yield. | Python |
function baz() {{ echo 'hello'; }} | function baz() {{ echo 'hello'; }} | Correct. | PHP |
DELETE FROM orders WHERE email=51 | DELETE FROM orders WHERE email=51; | Add semicolon. | SQL |
function handle(item)
print(item)
end | function handle(item)
print(item)
end | Correct. | Lua |
if (val = 18) | if (val == 18) | Use ==. | R |
for (int i=0; i<77; i++) {{}} | for (int i=0; i<77; i++) {{}} | Correct. | Java |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(15); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(15); | Correct. | Node.js |
let b = 28; b += 1; | let mut b = 28; b += 1; | Need mut to modify. | Rust |
System.out.println('data') | System.out.println('data'); | Add semicolon. | Java |
b = value | b = 'value' | Quote strings. | Python |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
list(26) | if length(list) >= 26, list(26), end | Check length. | MATLAB |
let bar = 60; let bar = 92; | let bar = 60; bar = 92; | Duplicate declaration. | JavaScript |
let vec=vec![99,40,93]; let head=&vec[0]; vec.push(25); | let mut vec=vec![99,40,93]; let head=vec[0]; vec.push(25); | Copy instead of reference. | Rust |
["output", 74] | ["output", 74] | Correct. | JSON |
if index = 45 | if index == 45 | Use ==. | Ruby |
fn baz() -> i32 {{ 55 }} | fn baz() -> i32 {{ 55 }} | Correct. | Rust |
$data[69] = 5; | if (isset($data[69])) $data[69] = 5; | Check existence. | PHP |
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