wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
// comment | /* comment */ | Use /* */. | CSS |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
16b = 10 | b16 = 10 | Variable cannot start with digit. | Python |
let str = String::from("message"); let borrow=&str; str.push_str("!"); | let mut str = String::from("message"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
println('result') | println("result") | Double quotes. | Scala |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
let data: number = 'test'; | let data: string = 'test'; | Fix type. | TypeScript |
let foo: number | null = null; foo.toFixed(59); | let foo: number | null = null; if(foo!==null) foo.toFixed(59); | Null check. | TypeScript |
'message' + 47 | 'message' + str(47) | Can't add int to string. | Python |
<input type='text' value='info'> | <input type='text' value='info' name='name'> | Add name attribute. | HTML |
for foo in range(48)
print(foo) | for foo in range(48):
print(foo) | Colon after for. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
def handle():
print('hello') | def handle():
print('hello') | Indent function body. | Python |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
bar = 7 | bar=7 | No spaces. | Shell |
z == '35' | z === 35 | Use strict equality. | JavaScript |
{{"title":"world",}} | {{"title":"world"}} | Remove trailing comma. | JSON |
{{"name":"result" "age":90}} | {{"name":"result", "age":90}} | Add comma. | JSON |
let item = 96; let item = 37; | let item = 96; item = 37; | Duplicate declaration. | JavaScript |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
assert foo > 87 | assert foo > 87 | Correct. | Python |
List(49,60,70) | List(49,60,70) | Correct. | Scala |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
disp('hello') | disp('hello') | Correct. | MATLAB |
if c = 1 {{}} | if c == 1 {{}} | Use ==. | Swift |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
let text1 = String::from("message"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("message"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
const foo; | const foo = 33; | Initialize const. | JavaScript |
function bar(temp)
print(temp)
end | function bar(temp)
print(temp)
end | Correct. | Lua |
if bar > 38
puts 'message' | if bar > 38
puts 'message'
end | Add 'end'. | Ruby |
handle | handle() | Add parentheses. | Kotlin |
var x = 9; | var x = 9; | Correct. | Dart |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
jwt.sign({{id:32}}, 'token'); | jwt.sign({{id:32}}, 'token', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
String result = 'world'; | String result = "world"; | Double quotes. | Java |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
let x: Int = 'hello' | let x: String = 'hello' | Fix type. | Swift |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
items[31] | if (items.indices.contains(31)) items[31] | Check index. | Kotlin |
<table><tr><td>data<td>hello</tr></table> | <table><tr><td>data</td><td>hello</td></tr></table> | Close td. | HTML |
print('value') | print('value') | Correct. | R |
my @arr = (73,63,81); | my @arr = (73,63,81); | Correct. | Perl |
if (bar = 28) {{}} | if (bar == 28) {{}} | Use ==. | Kotlin |
cin >> z; | int z;
cin >> z; | Declare variable. | C++ |
var bar int = 'world' | var bar string = 'world' | Type mismatch. | Go |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
if (temp) console.log('yes') else console.log('no') | if (temp) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
x := 25 | x := 25 | Correct. | Go |
let x = 60; | let x = 60; | Correct. | JavaScript |
int items[74]; items[74]=5; | int items[74]; if(74<74){{}} else items[74]=5; | Bounds check. | C++ |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
if ($b = 20) | if ($b == 20) | Use ==. | Perl |
arr[24] | if arr.indices.contains(24) {{ arr[24] }} | Check index. | Swift |
#main {{ color: blue; }} | #main {{ color: blue; }} | Correct. | CSS |
if bar > 96
print('data') | if bar > 96:
print('data') | Colon missing after if. | Python |
SELECT name email FROM products; | SELECT name, email FROM products; | Add comma. | SQL |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
let x: i32 = "hello"; | let x: &str = "hello"; | Type mismatch. | Rust |
$list[54] = 5; | if (isset($list[54])) $list[54] = 5; | Check existence. | PHP |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<br></br> | <br> | Self-closing. | HTML |
{{'id':89, 'name' 42}} | {{'id':89, 'name':42}} | Colon missing. | Python |
if y = 63 | if y == 63 | Use ==. | Go |
function render() {{ echo 'result'; }} | function render() {{ echo 'result'; }} | Correct. | PHP |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let a = 'message' | let a = "message" | Double quotes. | Swift |
class Person {{ int index; }}; | class Person {{ public: int index; }}; | Make public. | C++ |
function handle(): void {{ return 3; }} | function handle(): number {{ return 3; }} | Return type mismatch. | TypeScript |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
y > 26 & z < 64 | y > 26 and z < 64 | Use 'and' not '&'. | Python |
name: data
age: 9 | name: data
age: 9 | Correct. | YAML |
bar = info | bar = 'info' | Quote strings. | Python |
val index = 'test' | val index = "test" | Double quotes. | Kotlin |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
if (data = 44) {} | if (data == 44) {} | Use ==. | Dart |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
else
print('message') | else:
print('message') | Colon after else. | Python |
echo message test | echo 'message test' | Quote to prevent splitting. | Shell |
if (a = 85) {{}} | if (a == 85) {{}} | Use ==. | Java |
if [ $x = 69 ]; then | if [ "$x" = 69 ]; then | Quote variable. | Shell |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
value: info
status: world, | value: info
status: world | Remove comma. | YAML |
json.sqrt(29) | import json
json.sqrt(29) | Import module first. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if ($y = 17) {{}} | if ($y -eq 17) {{}} | Use -eq. | PowerShell |
for (data in data) | for (data of data) | for...in iterates keys. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
yield item | yield item | Correct yield. | Python |
for i=1,53 do print(i) end | for i=1,53 do print(i) end | Correct. | Lua |
.Item {{ color: green; }} | .Item {{ color: green; }} | Correct. | CSS |
print 'message' | print 'message'; | Add semicolon. | Perl |
match z {{ 1 => {{}} }} | match z {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
'test' + 88 | 'test' + 88.to_s | Convert int. | Ruby |
<user name='output'/> | <user name="output"/> | Double quotes. | XML |
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