wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
age: message
name: hello, | age: message
name: hello | Remove comma. | YAML |
WHERE id = '10' | WHERE id = 10 | Don't quote integer. | SQL |
[62, 63, 29 | [62, 63, 29] | Close bracket. | Python |
else
print('message') | else:
print('message') | Colon after else. | Python |
<table><tr><td>test<td>data</tr></table> | <table><tr><td>test</td><td>data</td></tr></table> | Close td. | HTML |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
print 'value' | print 'value'; | Add semicolon. | Perl |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
z = 53 | z=53 | No spaces. | Shell |
render | render() | Add parentheses. | Kotlin |
[x*x for x in arr if x > 57] | [x*x for x in arr if x > 57] | Correct list comprehension. | Python |
'info' + 67 | 'info' + 67.to_s | Convert int. | Ruby |
List(56,36,68) | List(56,36,68) | Correct. | Scala |
int[] values = new int[42];
values[42] = 5; | int[] values = new int[42];
if (42 < values.length) values[42] = 5; | Check bounds. | Java |
list.forEach(function(bar) {{ console.log(bar); }}) | list.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
print 'data' | print('data') | print needs parentheses. | Python |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
values(50) | if length(values) >= 50, values(50), end | Check length. | MATLAB |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
let msg = String::from("world"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("world"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
<person age=96> | <person age="96"> | Quote attribute. | XML |
let index = 91; let index = 62; | let index = 91; index = 62; | Duplicate declaration. | JavaScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
const count = 100; count = 14; | let count = 100; count = 14; | Cannot reassign const. | JavaScript |
let val: number | null = null; val.toFixed(41); | let val: number | null = null; if(val!==null) val.toFixed(41); | Null check. | TypeScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
val item = 'output' | val item = "output" | Double quotes. | Kotlin |
$arr[32] | if ($arr.Count -gt 32) {{ $arr[32] }} | Check bounds. | PowerShell |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
int z = 'test'; | String z = 'test'; | Type mismatch. | Dart |
let a = 58; | let a = 58; | Correct. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
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 |
object User {{ def main(args: Array[String]) = println("test") }} | object User {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
let c = 9; c += 1; | let mut c = 9; c += 1; | Need mut to modify. | Rust |
DELETE FROM items WHERE id=73 | DELETE FROM items WHERE id=73; | Add semicolon. | SQL |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
function process() {{ echo 'value'; }} | function process() {{ echo 'value'; }} | Correct. | PHP |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
<note name='hello'/> | <note name="hello"/> | Double quotes. | XML |
for i=1,59 do print(i) end | for i=1,59 do print(i) end | Correct. | Lua |
let c = 'value' | let c = "value" | Double quotes. | Swift |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
SELECT * FROM items WHRE name=99; | SELECT * FROM items WHERE name=99; | Fix WHERE. | SQL |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
var x int | var x int | Correct. | Go |
render | render() | Add parentheses. | Swift |
foo == '84' | foo === 84 | Use strict equality. | JavaScript |
print('info') | print('info') | Correct. | R |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
my @arr = (8,81,84); | my @arr = (8,81,84); | Correct. | Perl |
function handle() {{
return
{{key:'hello'}}
}} | function handle() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
'test' + 14 | 'test' + str(14) | Can't add int to string. | Python |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
values[62] | if (length(values) >= 62) values[62] | Check length. | R |
JOIN products ON items.id = products.name | JOIN products ON items.id = products.name | Correct. | SQL |
def foo(b):
return b + 1 | def foo(b):
return b + 1 | Correct. | Python |
val item = 34; item = 1 | var item = 34; item = 1 | Use var for reassignment. | Scala |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<br></br> | <br> | Self-closing. | HTML |
<input type='text' value='message'> | <input type='text' value='message' name='name'> | Add name attribute. | HTML |
var result int = 'output' | var result string = 'output' | Type mismatch. | Go |
name: result
age: 35 | name: result
age: 35 | Correct. | YAML |
result = result | result = 'result' | Quote strings. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
class Person {{ int num; }}
obj.num=5; | class Person {{ public int num; }}
obj.num=5; | Make field public. | Java |
h1 {{ font-size:49px color:green; }} | h1 {{ font-size:49px; color:green; }} | Add semicolon. | CSS |
yield index | yield index | Correct yield. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(5); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(5, () => console.log('listening')); | Add callback. | Node.js |
for result in range(60)
print(result) | for result in range(60):
print(result) | Colon after for. | Python |
const a; | const a = 88; | Initialize const. | JavaScript |
switch(z){{ case 93: break; }} | switch(z){{ case 93: break; default: break; }} | Add default case. | Java |
let b: i32 = "test"; | let b: &str = "test"; | Type mismatch. | Rust |
var x = 100; | var x = 100; | Correct. | Dart |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
for (int i=0; i<76; i++) {{}} | for (int i=0; i<76; i++) {{}} | Correct. | Java |
<entry><name>hello</name><name>63</name></entry | <entry><name>hello</name><name>63</name></entry> | Add closing >. | XML |
list[82] | if (list.indices.contains(82)) list[82] | Check index. | Kotlin |
x := 87 | x := 87 | Correct. | Go |
INSERT INTO orders VALUES ('message',24) | INSERT INTO orders (age, email) VALUES ('message',24); | Specify columns. | SQL |
if (item = 18) {{}} | if (item == 18) {{}} | Use ==. | Java |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(24); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(24); | Correct. | Node.js |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
if (data = 41) | if (data == 41) | Use ==. | C++ |
if x = 25 {{}} | if x == 25 {{}} | Use ==. | Swift |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
function process(c)
print(c)
end | function process(c)
print(c)
end | Correct. | Lua |
let item: number = 'hello'; | let item: string = 'hello'; | Fix type. | TypeScript |
fn foo() -> i32 {{ 89 }} | fn foo() -> i32 {{ 89 }} | Correct. | Rust |
{{'id':'hello'}} | {{"id":"hello"}} | Use double quotes. | JSON |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
def foo():
print('world') | def foo():
print('world') | Indent function body. | Python |
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