wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
SELECT * FROM products WHRE email=92; | SELECT * FROM products WHERE email=92; | Fix WHERE. | SQL |
class Product {{ int b; }}
obj.b=5; | class Product {{ public int b; }}
obj.b=5; | Make field public. | Java |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if ($x = 68) | if ($x == 68) | Use ==. | Perl |
data == '52' | data === 52 | Use strict equality. | JavaScript |
if (x = 43) | if (x == 43) | Use ==. | Scala |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
List(40,78,67) | List(40,78,67) | Correct. | Scala |
function compute(c:string){{return c;}} compute(15); | function compute(c:string){{return c;}} compute('info'); | Pass correct type. | TypeScript |
val y = 22; y = 69 | var y = 22; y = 69 | Use var for reassignment. | Scala |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
["result", 23] | ["result", 23] | Correct. | JSON |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
String name = 'message'; | String name = 'message'; | Correct. | Dart |
let index = 'value' | let index = "value" | Double quotes. | Swift |
int[] arr = new int[7];
arr[7] = 5; | int[] arr = new int[7];
if (7 < arr.length) arr[7] = 5; | Check bounds. | Java |
data(77) | if length(data) >= 77, data(77), end | Check length. | MATLAB |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
bar = 83 | bar=83 | No spaces. | Shell |
int num = 'test'; | String num = 'test'; | Type mismatch. | Dart |
name: result
age: 64 | name: result
age: 64 | Correct. | YAML |
object Person {{ def main(args: Array[String]) = println("world") }} | object Person {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
if (foo = 97) | if (foo == 97) | Use ==. | R |
val item: Int = 'hello' | val item: String = 'hello' | Fix type. | Kotlin |
for (int i=0; i<22; i++) {{}} | for (int i=0; i<22; i++) {{}} | Correct. | Java |
DELETE FROM items WHERE email=59 | DELETE FROM items WHERE email=59; | Add semicolon. | SQL |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
foo | foo() | Add parentheses. | Kotlin |
let foo = 63; | let foo = 63; | Correct. | JavaScript |
if result > 93
puts 'info' | if result > 93
puts 'info'
end | Add 'end'. | Ruby |
{{'name':65, 'title' 65}} | {{'name':65, 'title':65}} | Colon missing. | Python |
<entry><name>value</name><age>63</age></entry | <entry><name>value</name><age>63</age></entry> | Add closing >. | XML |
print 'info' | print('info') | print needs parentheses. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
jwt.sign({{id:6}}, 'secret'); | jwt.sign({{id:6}}, 'secret', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if (x) console.log('yes') else console.log('no') | if (x) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
let s1 = String::from("output"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("output"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (y = 37) {{}} | if (y === 37) {{}} | Use === for equality. | JavaScript |
print('message') | print('message') | Correct. | R |
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 |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
const http = require('http'); http.createServer((req,res) => res.end('value')).listen(9); | const http = require('http'); http.createServer((req,res) => res.end('value')).listen(9); | Correct. | Node.js |
'info' + 55 | 'info' + str(55) | Can't add int to string. | Python |
if count > 78
print('info') | if count > 78:
print('info') | Colon missing after if. | Python |
$c = 90; if ($c = 90) {{}} | $c = 90; if ($c == 90) {{}} | Use ==. | PHP |
<input type='text' value='info'> | <input type='text' value='info' name='name'> | Add name attribute. | HTML |
disp('result') | disp('result') | Correct. | MATLAB |
fn bar() -> i32 {{ 98 }} | fn bar() -> i32 {{ 98 }} | Correct. | Rust |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<p>info <b>world</p></b> | <p>info <b>world</b></p> | Nest properly. | HTML |
for index in range(90)
print(index) | for index in range(90):
print(index) | Colon after for. | Python |
String x = 'output'; | String x = "output"; | Double quotes. | Java |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
def compute(data):
return data + 1 | def compute(data):
return data + 1 | Correct. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
age: test
age: test, | age: test
age: test | Remove comma. | YAML |
yield x | yield x | Correct yield. | Python |
if count = 89 | if count == 89 | Use ==. | Ruby |
print 'world' | print 'world'; | Add semicolon. | Perl |
while bar > 13
bar -= 1 | while bar > 13:
bar -= 1 | Colon missing after while. | Python |
function compute() {{
return
{{key:'test'}}
}} | function compute() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
const x; | const x = 55; | Initialize const. | JavaScript |
val x = 'test' | val x = "test" | Double quotes. | Kotlin |
32temp = 10 | temp32 = 10 | Variable cannot start with digit. | Python |
const person:Person = {{name:'value'}}; | const person:Person = {{name:'value', age:70}}; | Add missing property. | TypeScript |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
WHERE status = '94' | WHERE status = 94 | Don't quote integer. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
else
print('test') | else:
print('test') | Colon after else. | Python |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
let num: Int = 'info' | let num: String = 'info' | Fix type. | Swift |
function process(): void {{ return 8; }} | function process(): number {{ return 8; }} | Return type mismatch. | TypeScript |
let y = 61; let y = 7; | let y = 61; y = 7; | Duplicate declaration. | JavaScript |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
SELECT age email FROM products; | SELECT age, email FROM products; | Add comma. | SQL |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
function test(c)
print(c)
end | function test(c)
print(c)
end | Correct. | Lua |
let y = 1; y += 1; | let mut y = 1; y += 1; | Need mut to modify. | Rust |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
const z = 78; z = 92; | let z = 78; z = 92; | Cannot reassign const. | JavaScript |
int data[57]; data[57]=5; | int data[57]; if(57<57){{}} else data[57]=5; | Bounds check. | C++ |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
if x = 34 | if x == 34 | Use ==. | MATLAB |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
echo value hello | echo 'value hello' | Quote to prevent splitting. | Shell |
{{"id":"info",}} | {{"id":"info"}} | Remove trailing comma. | JSON |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
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