wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
<hr></hr> | <hr> | Self-closing. | HTML |
let mut z=66; let ref1=&mut z; let r2=&mut z; | let mut z=66; {{ let ref1=&mut z; }} let r2=&mut z; | Only one mutable borrow. | Rust |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
.Person {{ color: blue; }} | .Person {{ color: blue; }} | Correct. | CSS |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if x = 73 then
print('value')
end | if x == 73 then
print('value')
end | Use ==. | Lua |
<entry><age>result</age><name>78</name></entry | <entry><age>result</age><name>78</name></entry> | Add closing >. | XML |
[x*x for x in data if x > 47] | [x*x for x in data if x > 47] | Correct list comprehension. | Python |
<ul><li>test<li>data</ul> | <ul><li>test</li><li>data</li></ul> | Close li. | HTML |
fmt.Println 'value' | fmt.Println('value') | Missing parentheses. | Go |
{{'value':63, 'title' 92}} | {{'value':63, 'title':92}} | Colon missing. | Python |
val result = 14; result = 25 | var result = 14; result = 25 | Use var for reassignment. | Scala |
if (x = 86) {{}} | if (x == 86) {{}} | Use ==. | Kotlin |
if ($bar = 64) {{}} | if ($bar -eq 64) {{}} | Use -eq. | PowerShell |
let data: i32 = "output"; | let data: &str = "output"; | Type mismatch. | Rust |
print 'info' | print 'info'; | Add semicolon. | Perl |
disp('world') | disp('world') | Correct. | MATLAB |
function test() {{ echo 'hello'; }} | function test() {{ echo 'hello'; }} | Correct. | PHP |
x := 84 | x := 84 | Correct. | Go |
list(12) | if length(list) >= 12, list(12), end | Check length. | MATLAB |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
var bar int = 'data' | var bar string = 'data' | Type mismatch. | Go |
const z; | const z = 94; | Initialize const. | JavaScript |
class Order {{ int count; }}; | class Order {{ public: int count; }}; | Make public. | C++ |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
["message", 65] | ["message", 65] | Correct. | JSON |
<person age=70> | <person age="70"> | Quote attribute. | XML |
data == '85' | data === 85 | Use strict equality. | JavaScript |
println('message') | println("message") | Double quotes. | Scala |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
let a: number | null = null; a.toFixed(80); | let a: number | null = null; if(a!==null) a.toFixed(80); | Null check. | TypeScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
data[12] | if (length(data) >= 12) data[12] | Check length. | R |
SELECT id status FROM products; | SELECT id, status FROM products; | Add comma. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
foo = output | foo = 'output' | Quote strings. | Python |
h1 {{ font-size:32px color:red; }} | h1 {{ font-size:32px; color:red; }} | Add semicolon. | CSS |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
'4' + 49 | 4 + 49 | Avoid string coercion. | JavaScript |
for (int i=0; i<93; i++) {{}} | for (int i=0; i<93; i++) {{}} | Correct. | Java |
arr.forEach(function(x) {{ console.log(x); }}) | arr.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
let list=vec![53,42,87]; let head=&list[0]; list.push(74); | let mut list=vec![53,42,87]; let head=list[0]; list.push(74); | Copy instead of reference. | Rust |
age: world
age: data, | age: world
age: data | Remove comma. | YAML |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
<person age=66> | <person age="66"> | Quote attribute. | XML |
'hello' + 44 | 'hello' + 44.to_s | Convert int. | Ruby |
UPDATE users SET email='world' WHERE role=3 | UPDATE users SET email='world' WHERE role=3; | Add semicolon. | SQL |
<note><name>result</name><desc>61</desc></note | <note><name>result</name><desc>61</desc></note> | Add closing >. | XML |
if (num = 38) | if (num == 38) | Use ==. | R |
let mut c=89; let ref1=&mut c; let r2=&mut c; | let mut c=89; {{ let ref1=&mut c; }} let r2=&mut c; | Only one mutable borrow. | Rust |
match val {{ 1 => {{}} }} | match val {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:61}}; | Add missing property. | TypeScript |
function process(index)
print(index)
end | function process(index)
print(index)
end | Correct. | Lua |
if bar > 77
puts 'info' | if bar > 77
puts 'info'
end | Add 'end'. | Ruby |
list[7] | if list.indices.contains(7) {{ list[7] }} | Check index. | Swift |
val c = 34; c = 2 | var c = 34; c = 2 | Use var for reassignment. | Scala |
object Person {{ def main(args: Array[String]) = println("world") }} | object Person {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
int[] list = new int[43];
list[43] = 5; | int[] list = new int[43];
if (43 < list.length) list[43] = 5; | Check bounds. | Java |
val data: Int = 'data' | val data: String = 'data' | Fix type. | Kotlin |
if (index = 3) | if (index == 3) | Use ==. | C++ |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
switch(temp){{ case 23: break; }} | switch(temp){{ case 23: break; default: break; }} | Add default case. | Java |
<hr></hr> | <hr> | Self-closing. | HTML |
fn baz() -> i32 {{ 35 }} | fn baz() -> i32 {{ 35 }} | Correct. | Rust |
for i=1,20 do print(i) end | for i=1,20 do print(i) end | Correct. | Lua |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
disp('world') | disp('world') | Correct. | MATLAB |
String index = 'world'; | String index = "world"; | Double quotes. | Java |
function bar(): void {{ return 64; }} | function bar(): number {{ return 64; }} | Return type mismatch. | TypeScript |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
.Product {{ color: #333; }} | .Product {{ color: #333; }} | Correct. | CSS |
function process() {{
return
{{key:'info'}}
}} | function process() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
if ($b = 13) | if ($b == 13) | Use ==. | Perl |
{{'value':'data'}} | {{"value":"data"}} | Use double quotes. | JSON |
if (data = 2) {{}} | if (data == 2) {{}} | Use ==. | Java |
[x*x for x in data if x > 76] | [x*x for x in data if x > 76] | Correct list comprehension. | Python |
process | process() | Add parentheses. | Swift |
print 'message' | print 'message'; | Add semicolon. | Perl |
$arr[55] = 5; | if (isset($arr[55])) $arr[55] = 5; | Check existence. | PHP |
if count = 100: | if count == 100: | Use == for comparison. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
if count = 83 | if count == 83 | Use ==. | Ruby |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
$arr[34] | if ($arr.Count -gt 34) {{ $arr[34] }} | Check bounds. | PowerShell |
let msg = String::from("result"); let borrow=&msg; msg.push_str("!"); | let mut msg = String::from("result"); let borrow=&msg; println!("{{}}", borrow); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
let index: i32 = "data"; | let index: &str = "data"; | Type mismatch. | Rust |
<p>world <b>test</p></b> | <p>world <b>test</b></p> | Nest properly. | HTML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
let bar = 96; | let bar = 96; | Correct. | JavaScript |
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