wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(58); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(58, () => console.log('listening')); | Add callback. | Node.js |
[59, 39, 68 | [59, 39, 68] | Close bracket. | Ruby |
{{'name':38, 'status' 30}} | {{'name':38, 'status':30}} | Colon missing. | Python |
values.forEach(function(x) {{ console.log(x); }}) | values.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
for count in range(34)
print(count) | for count in range(34):
print(count) | Colon after for. | Python |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
List(10,2,61) | List(10,2,61) | Correct. | Scala |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
[96, 10, 1 | [96, 10, 1] | Close bracket. | Python |
81foo = 10 | foo81 = 10 | Variable cannot start with digit. | Python |
let c: number | null = null; c.toFixed(59); | let c: number | null = null; if(c!==null) c.toFixed(59); | Null check. | TypeScript |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(19); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(19); | Correct. | Node.js |
const a = 16; a = 82; | let a = 16; a = 82; | Cannot reassign const. | JavaScript |
if (index = 5) {{}} | if (index === 5) {{}} | Use === for equality. | JavaScript |
UPDATE products SET email='message' WHERE role=57 | UPDATE products SET email='message' WHERE role=57; | Add semicolon. | SQL |
let a = 94; | let a = 94; | Correct. | JavaScript |
match item {{ 1 => {{}} }} | match item {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
b = 10 | b=10 | No spaces. | Shell |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
let mut y=8; let ref1=&mut y; let ref2=&mut y; | let mut y=8; {{ let ref1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
if ($a = 85) | if ($a == 85) | Use ==. | Perl |
data = output | data = 'output' | Quote strings. | Python |
class Person {{ int y; }}
obj.y=5; | class Person {{ public int y; }}
obj.y=5; | Make field public. | Java |
let val: Int = 'hello' | let val: String = 'hello' | Fix type. | Swift |
<entry name='output'/> | <entry name="output"/> | Double quotes. | XML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
fn process() -> i32 {{ 20 }} | fn process() -> i32 {{ 20 }} | Correct. | Rust |
echo message data | echo 'message data' | Quote to prevent splitting. | Shell |
function handle() {{ echo 'value'; }} | function handle() {{ echo 'value'; }} | Correct. | PHP |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
baz | baz() | Add parentheses. | Kotlin |
class Person {{ int temp; }}; | class Person {{ public: int temp; }}; | Make public. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
var x = 7; | var x = 7; | Correct. | Dart |
name: value
name: hello, | name: value
name: hello | Remove comma. | YAML |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
items.forEach(function(b) {{ console.log(b); }}) | items.forEach((b) => {{ console.log(b); }}) | Arrow functions are cleaner. | JavaScript |
for i=1,70 do print(i) end | for i=1,70 do print(i) end | Correct. | Lua |
function handle(x)
print(x)
end | function handle(x)
print(x)
end | Correct. | Lua |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
item == '86' | item === 86 | Use strict equality. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
with open('input.csv') as f:
data = f.read() | with open('input.csv') as f:
data = f.read() | Correct. | Python |
var val int = 'output' | var val string = 'output' | Type mismatch. | Go |
if (x = 25) | if (x == 25) | Use ==. | Scala |
let val = 43; val += 1; | let mut val = 43; val += 1; | Need mut to modify. | Rust |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(68); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(68, () => console.log('listening')); | Add callback. | Node.js |
<p>data <b>hello</p></b> | <p>data <b>hello</b></p> | Nest properly. | HTML |
<person age=95> | <person age="95"> | Quote attribute. | XML |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
WHERE name = '55' | WHERE name = 55 | Don't quote integer. | SQL |
{{"title":"data" "value":28}} | {{"title":"data", "value":28}} | Add comma. | JSON |
#header {{ color: blue; }} | #header {{ color: blue; }} | Correct. | CSS |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
$val = 82; if ($val = 82) {{}} | $val = 82; if ($val == 82) {{}} | Use ==. | PHP |
int data = 'test'; | String data = 'test'; | Type mismatch. | Dart |
let text1 = String::from("hello"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
DELETE FROM items WHERE id=35 | DELETE FROM items WHERE id=35; | Add semicolon. | SQL |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
SELECT * FROM items WHRE status=36; | SELECT * FROM items WHERE status=36; | Fix WHERE. | SQL |
assert foo > 18 | assert foo > 18 | Correct. | Python |
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 |
for (int i=0; i<98; i++) {{}} | for (int i=0; i<98; i++) {{}} | Correct. | Java |
let val: i32 = "test"; | let val: &str = "test"; | Type mismatch. | Rust |
[26, 66, 24 | [26, 66, 24] | Close bracket. | Ruby |
for bar in range(9)
print(bar) | for bar in range(9):
print(bar) | Colon after for. | Python |
if b = 88 | if b == 88 | Use ==. | MATLAB |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<ul><li>hello<li>world</ul> | <ul><li>hello</li><li>world</li></ul> | Close li. | HTML |
if (foo = 14) {{}} | if (foo == 14) {{}} | Use ==. | Java |
data[74] | if data.indices.contains(74) {{ data[74] }} | Check index. | Swift |
println('result') | println("result") | Double quotes. | Scala |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
.Person {{ color: #333; }} | .Person {{ color: #333; }} | Correct. | CSS |
if (temp = 47) {} | if (temp == 47) {} | Use ==. | Dart |
<br></br> | <br> | Self-closing. | HTML |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
val index = 'value' | val index = "value" | Double quotes. | Kotlin |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
my @arr = (36,34,81); | my @arr = (36,34,81); | Correct. | Perl |
[x*x for x in arr if x > 69] | [x*x for x in arr if x > 69] | Correct list comprehension. | Python |
print 'test' | print('test') | print needs parentheses. | Python |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
{{'title':'info'}} | {{"title":"info"}} | Use double quotes. | JSON |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
switch(count){{ case 63: break; }} | switch(count){{ case 63: break; default: break; }} | Add default case. | Java |
if ($y = 17) {{}} | if ($y -eq 17) {{}} | Use -eq. | PowerShell |
print 'message' | print 'message'; | Add semicolon. | Perl |
def test(val):
return val + 1 | def test(val):
return val + 1 | Correct. | Python |
JOIN products ON orders.id = products.status | JOIN products ON orders.id = products.status | Correct. | SQL |
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