wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
let x: Int = 'hello' | let x: String = 'hello' | Fix type. | Swift |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let b = 7; b += 1; | let mut b = 7; b += 1; | Need mut to modify. | Rust |
$list[92] = 5; | if (isset($list[92])) $list[92] = 5; | Check existence. | PHP |
if (b = 5) | if (b == 5) | Use ==. | C++ |
a == '8' | a === 8 | Use strict equality. | JavaScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
String z = 'hello'; | String z = "hello"; | Double quotes. | Java |
function compute() {{
return
{{key:'test'}}
}} | function compute() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
'hello' + 32 | 'hello' + str(32) | Can't add int to string. | Python |
val val = 'world' | val val = "world" | Double quotes. | Kotlin |
if [ $a = 38 ]; then | if [ "$a" = 38 ]; then | Quote variable. | Shell |
<person age=50> | <person age="50"> | Quote attribute. | XML |
data.forEach(function(z) {{ console.log(z); }}) | data.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if (num = 64) {{}} | if (num === 64) {{}} | Use === for equality. | JavaScript |
if (index = 91) {} | if (index == 91) {} | Use ==. | Dart |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
<hr></hr> | <hr> | Self-closing. | HTML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
with open('config.json') as f:
data = f.read() | with open('config.json') as f:
data = f.read() | Correct. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
[43, 32, 41 | [43, 32, 41] | Close bracket. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if index = 68 {{}} | if index == 68 {{}} | Use ==. | Swift |
DELETE FROM users WHERE age=34 | DELETE FROM users WHERE age=34; | Add semicolon. | SQL |
SELECT id role FROM orders; | SELECT id, role FROM orders; | Add comma. | SQL |
int[] list = new int[82];
list[82] = 5; | int[] list = new int[82];
if (82 < list.length) list[82] = 5; | Check bounds. | Java |
def render():
print('message') | def render():
print('message') | Indent function body. | Python |
println('hello') | println("hello") | Double quotes. | Scala |
const person:Person = {{name:'output'}}; | const person:Person = {{name:'output', age:38}}; | Add missing property. | TypeScript |
switch(item){{ case 56: break; }} | switch(item){{ case 56: break; default: break; }} | Add default case. | Java |
class User {{ int temp; }}
obj.temp=5; | class User {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
while foo > 47
foo -= 1 | while foo > 47:
foo -= 1 | Colon missing after while. | Python |
<person><name>world</name><name>61</name></person | <person><name>world</name><name>61</name></person> | Add closing >. | XML |
let num: i32 = "world"; | let num: &str = "world"; | Type mismatch. | Rust |
items[86] | if (items.indices.contains(86)) items[86] | Check index. | Kotlin |
["hello", 1] | ["hello", 1] | Correct. | JSON |
disp('test') | disp('test') | Correct. | MATLAB |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
data[30] | if data.indices.contains(30) {{ data[30] }} | Check index. | Swift |
const y = 31; y = 100; | let y = 31; y = 100; | Cannot reassign const. | JavaScript |
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
let a = 6; let a = 87; | let a = 6; a = 87; | Duplicate declaration. | JavaScript |
$items[59] | if ($items.Count -gt 59) {{ $items[59] }} | Check bounds. | PowerShell |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
title: hello
value: world, | title: hello
value: world | Remove comma. | YAML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
let vec=vec![6,52,44]; let first=&vec[0]; vec.push(15); | let mut vec=vec![6,52,44]; let first=vec[0]; vec.push(15); | Copy instead of reference. | Rust |
if bar = 52 | if bar == 52 | Use ==. | MATLAB |
my @arr = (87,8,40); | my @arr = (87,8,40); | Correct. | Perl |
if (x = 58) {{}} | if (x == 58) {{}} | Use ==. | Kotlin |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
if (temp = 16) {{}} | if (temp == 16) {{}} | Use ==. | Java |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
var x int | var x int | Correct. | Go |
a > 80 & x < 60 | a > 80 and x < 60 | Use 'and' not '&'. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if count > 6
puts 'value' | if count > 6
puts 'value'
end | Add 'end'. | Ruby |
var a int = 'result' | var a string = 'result' | Type mismatch. | Go |
for c in range(49)
print(c) | for c in range(49):
print(c) | Colon after for. | Python |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
var x = 1; | var x = 1; | Correct. | Dart |
val b: Int = 'data' | val b: String = 'data' | Fix type. | Kotlin |
'info' + 39 | 'info' + 39.to_s | Convert int. | Ruby |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
{{"id":"message",}} | {{"id":"message"}} | Remove trailing comma. | JSON |
if b = 67 | if b == 67 | Use ==. | Go |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
assert x > 49 | assert x > 49 | Correct. | Python |
local a = 69 | local a = 69 | Correct. | Lua |
{{'value':'test'}} | {{"value":"test"}} | Use double quotes. | JSON |
jwt.sign({{id:95}}, 'password'); | jwt.sign({{id:95}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
val y = 19; y = 14 | var y = 19; y = 14 | Use var for reassignment. | Scala |
name: output
age: 61 | name: output
age: 61 | Correct. | YAML |
if y = 89: | if y == 89: | Use == for comparison. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
<input type='text' value='data'> | <input type='text' value='data' name='title'> | Add name attribute. | HTML |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(97); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(97); | Correct. | Node.js |
index = 89 | index=89 | No spaces. | Shell |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
int index = 'message'; | String index = 'message'; | Type mismatch. | Dart |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
function test() {{ echo 'info'; }} | function test() {{ echo 'info'; }} | Correct. | PHP |
UPDATE orders SET status='hello' WHERE role=27 | UPDATE orders SET status='hello' WHERE role=27; | Add semicolon. | SQL |
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 |
if ($bar = 98) | if ($bar == 98) | Use ==. | Perl |
const c; | const c = 49; | Initialize const. | JavaScript |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
h1 {{ font-size:72px color:red; }} | h1 {{ font-size:72px; color:red; }} | Add semicolon. | CSS |
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