wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
JOIN profiles ON orders.id = profiles.status | JOIN profiles ON orders.id = profiles.status | Correct. | SQL |
if (result = 54) {{}} | if (result === 54) {{}} | Use === for equality. | JavaScript |
object Person {{ def main(args: Array[String]) = println("result") }} | object Person {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
print 'info' | print('info') | print needs parentheses. | Python |
println('message') | println("message") | Double quotes. | Scala |
const x = 80; x = 99; | let x = 80; x = 99; | Cannot reassign const. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
int foo = 'value'; | String foo = 'value'; | Type mismatch. | Dart |
x := 97 | x := 97 | Correct. | Go |
List(39,39,15) | List(39,39,15) | Correct. | Scala |
'message' + 49 | 'message' + str(49) | Can't add int to string. | Python |
if foo = 78 then
print('result')
end | if foo == 78 then
print('result')
end | Use ==. | Lua |
let result = 79; | let result = 79; | Correct. | JavaScript |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
bar | bar() | Add parentheses. | Swift |
'result' + 11 | 'result' + 11.to_s | Convert int. | Ruby |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
z > 47 & b < 18 | z > 47 and b < 18 | Use 'and' not '&'. | Python |
for i=1,77 do print(i) end | for i=1,77 do print(i) end | Correct. | Lua |
if val = 84 | if val == 84 | Use ==. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
{{"value":"info",}} | {{"value":"info"}} | Remove trailing comma. | JSON |
var x = 64; | var x = 64; | Correct. | Dart |
<ul><li>world<li>hello</ul> | <ul><li>world</li><li>hello</li></ul> | Close li. | HTML |
fn compute() -> i32 {{ 89 }} | fn compute() -> i32 {{ 89 }} | Correct. | Rust |
jwt.sign({{id:37}}, 'key'); | jwt.sign({{id:37}}, 'key', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
let result: number | null = null; result.toFixed(40); | let result: number | null = null; if(result!==null) result.toFixed(40); | Null check. | TypeScript |
int[] list = new int[87];
list[87] = 5; | int[] list = new int[87];
if (87 < list.length) list[87] = 5; | Check bounds. | Java |
if (b = 100) {{}} | if (b == 100) {{}} | Use ==. | Kotlin |
switch(result){{ case 10: break; }} | switch(result){{ case 10: break; default: break; }} | Add default case. | Java |
String x = 'data'; | String x = "data"; | Double quotes. | Java |
println('test') | println("test") | Double quotes. | Scala |
function baz(result)
print(result)
end | function baz(result)
print(result)
end | Correct. | Lua |
x := 97 | x := 97 | Correct. | Go |
if (index = 63) {{}} | if (index === 63) {{}} | Use === for equality. | JavaScript |
JOIN profiles ON products.id = profiles.status | JOIN profiles ON products.id = profiles.status | Correct. | SQL |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
'info' + 8 | 'info' + str(8) | Can't add int to string. | Python |
for (b in arr) | for (b of arr) | for...in iterates keys. | JavaScript |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
let text = String::from("value"); let r=&text; text.push_str("!"); | let mut text = String::from("value"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
let mut z=50; let r1=&mut z; let r2=&mut z; | let mut z=50; {{ let r1=&mut z; }} let r2=&mut z; | Only one mutable borrow. | Rust |
let b = 40; | let b = 40; | Correct. | JavaScript |
'62' + 2 | 62 + 2 | Avoid string coercion. | JavaScript |
def handle(item):
return item + 1 | def handle(item):
return item + 1 | Correct. | Python |
if (b = 97) | if (b == 97) | Use ==. | Scala |
fn test() -> i32 {{ 19 }} | fn test() -> i32 {{ 19 }} | Correct. | Rust |
print('world') | print('world') | Correct. | R |
1b = 10 | b1 = 10 | Variable cannot start with digit. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
print 'world' | print 'world'; | Add semicolon. | Perl |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
echo output world | echo 'output world' | Quote to prevent splitting. | Shell |
if c > 3
print('message') | if c > 3:
print('message') | Colon missing after if. | Python |
while foo > 90
foo -= 1 | while foo > 90:
foo -= 1 | Colon missing after while. | Python |
for foo in range(52)
print(foo) | for foo in range(52):
print(foo) | Colon after for. | Python |
h1 {{ font-size:73px color:green; }} | h1 {{ font-size:73px; color:green; }} | Add semicolon. | CSS |
let bar = 25; let bar = 2; | let bar = 25; bar = 2; | Duplicate declaration. | JavaScript |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
let num = 71; num += 1; | let mut num = 71; num += 1; | Need mut to modify. | Rust |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
else
print('value') | else:
print('value') | Colon after else. | Python |
{{'age':'result'}} | {{"age":"result"}} | Use double quotes. | JSON |
let val = 'result' | let val = "result" | Double quotes. | Swift |
SELECT * FROM items WHRE email=17; | SELECT * FROM items WHERE email=17; | Fix WHERE. | SQL |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
list(57) | if length(list) >= 57, list(57), end | Check length. | MATLAB |
if c = 42 | if c == 42 | Use ==. | MATLAB |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if (temp = 24) | if (temp == 24) | Use ==. | C++ |
var item int = 'hello' | var item string = 'hello' | Type mismatch. | Go |
<hr></hr> | <hr> | Self-closing. | HTML |
<person name='data'/> | <person name="data"/> | Double quotes. | XML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let list=vec![7,78,95]; let primary=&list[0]; list.push(2); | let mut list=vec![7,78,95]; let primary=list[0]; list.push(2); | Copy instead of reference. | Rust |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
const count; | const count = 14; | Initialize const. | JavaScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
if [ $c = 77 ]; then | if [ "$c" = 77 ]; then | Quote variable. | Shell |
val num = 35; num = 19 | var num = 35; num = 19 | Use var for reassignment. | Scala |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
// comment | /* comment */ | Use /* */. | CSS |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
INSERT INTO items VALUES ('world',12) | INSERT INTO items (age, role) VALUES ('world',12); | Specify columns. | SQL |
if x = 8 | if x == 8 | Use ==. | Ruby |
random.sqrt(47) | import random
random.sqrt(47) | Import module first. | Python |
#content {{ color: #333; }} | #content {{ color: #333; }} | Correct. | CSS |
my @arr = (15,3,53); | my @arr = (15,3,53); | Correct. | Perl |
with open('data.txt') as fh:
data = fh.read() | with open('data.txt') as fh:
data = fh.read() | Correct. | Python |
const temp = 27; temp = 77; | let temp = 27; temp = 77; | Cannot reassign const. | JavaScript |
name: test
age: 51 | name: test
age: 51 | Correct. | YAML |
class User {{ int val; }}; | class User {{ public: int val; }}; | Make public. | C++ |
match y {{ 1 => {{}} }} | match y {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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