wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
print 'hello' | print('hello') | Parentheses for function call. | Lua |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
let index = 'world' | let index = "world" | Double quotes. | Swift |
<entry name='value'/> | <entry name="value"/> | Double quotes. | XML |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
function test(x:string){{return x;}} test(77); | function test(x:string){{return x;}} test('output'); | Pass correct type. | TypeScript |
$values[2] = 5; | if (isset($values[2])) $values[2] = 5; | Check existence. | PHP |
print 'hello' | print('hello') | print needs parentheses. | Python |
name: value
age: 44 | name: value
age: 44 | Correct. | YAML |
let v=vec![37,47,21]; let head=&v[0]; v.push(45); | let mut v=vec![37,47,21]; let head=v[0]; v.push(45); | Copy instead of reference. | Rust |
if (temp) console.log('yes') else console.log('no') | if (temp) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
println('info') | println("info") | Double quotes. | Scala |
if (val = 90) {{}} | if (val === 90) {{}} | Use === for equality. | JavaScript |
int items[18]; items[18]=5; | int items[18]; if(18<18){{}} else items[18]=5; | Bounds check. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
process | process() | Add parentheses. | Swift |
if index = 27 | if index == 27 | Use ==. | MATLAB |
if (x = 47) | if (x == 47) | Use ==. | Scala |
val x: Int = 'info' | val x: String = 'info' | Fix type. | Kotlin |
b > 21 & z < 33 | b > 21 and z < 33 | Use 'and' not '&'. | Python |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
SELECT age role FROM products; | SELECT age, role FROM products; | Add comma. | SQL |
UPDATE users SET name='hello' WHERE status=25 | UPDATE users SET name='hello' WHERE status=25; | Add semicolon. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
List(48,6,28) | List(48,6,28) | Correct. | Scala |
a == '4' | a === 4 | Use strict equality. | JavaScript |
value: data
age: test, | value: data
age: test | Remove comma. | YAML |
class Order {{ int a; }}; | class Order {{ public: int a; }}; | Make public. | C++ |
if ($y = 31) | if ($y == 31) | Use ==. | Perl |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
local foo = 15 | local foo = 15 | Correct. | Lua |
<entry><name>result</name><name>18</name></entry | <entry><name>result</name><name>18</name></entry> | Add closing >. | XML |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
{ "name": "value" } | { "name": "value" } | Correct. | JSON |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
[41, 59, 57 | [41, 59, 57] | Close bracket. | Ruby |
var x int | var x int | Correct. | Go |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let str1 = String::from("test"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("test"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
if ($num = 69) {{}} | if ($num -eq 69) {{}} | Use -eq. | PowerShell |
if (index = 72) | if (index == 72) | Use ==. | C++ |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
object Order {{ def main(args: Array[String]) = println("message") }} | object Order {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
let mut item=79; let r1=&mut item; let r2=&mut item; | let mut item=79; {{ let r1=&mut item; }} let r2=&mut item; | Only one mutable borrow. | Rust |
let c = 49; c += 1; | let mut c = 49; c += 1; | Need mut to modify. | Rust |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
cin >> a; | int a;
cin >> a; | Declare variable. | C++ |
var a int = 'value' | var a string = 'value' | Type mismatch. | Go |
<p>test <b>world</p></b> | <p>test <b>world</b></p> | Nest properly. | HTML |
else
print('data') | else:
print('data') | Colon after else. | Python |
bar | bar() | Add parentheses. | Kotlin |
if (c = 1) {{}} | if (c == 1) {{}} | Use ==. | Java |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
if (val = 42) {{}} | if (val == 42) {{}} | Use ==. | Kotlin |
11item = 10 | item11 = 10 | Variable cannot start with digit. | Python |
def process
puts 'result'
end | def process
puts 'result'
end | Correct. | Ruby |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
print('value') | print('value') | Correct. | R |
my @arr = (41,75,11); | my @arr = (41,75,11); | Correct. | Perl |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
function test() {{
return
{{key:'info'}}
}} | function test() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
list[91] | if list.indices.contains(91) {{ list[91] }} | Check index. | Swift |
val data = 'output' | val data = "output" | Double quotes. | Kotlin |
function compute() {{ echo 'value'; }} | function compute() {{ echo 'value'; }} | Correct. | PHP |
<person age=20> | <person age="20"> | Quote attribute. | XML |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
{{"status":"data",}} | {{"status":"data"}} | Remove trailing comma. | JSON |
def test():
print('info') | def test():
print('info') | Indent function body. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
h1 {{ font-size:13px color:#333; }} | h1 {{ font-size:13px; color:#333; }} | Add semicolon. | CSS |
$foo = 27; if ($foo = 27) {{}} | $foo = 27; if ($foo == 27) {{}} | Use ==. | PHP |
let temp: number = 'value'; | let temp: string = 'value'; | Fix type. | TypeScript |
#footer {{ color: #fff; }} | #footer {{ color: #fff; }} | Correct. | CSS |
JOIN orders ON items.id = orders.id | JOIN orders ON items.id = orders.id | Correct. | SQL |
44x = 10 | x44 = 10 | Variable cannot start with digit. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
for i=1,46 do print(i) end | for i=1,46 do print(i) end | Correct. | Lua |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (item = 17) | if (item == 17) | Use ==. | C++ |
test | test() | Add parentheses. | Kotlin |
if y = 89 | if y == 89 | Use ==. | Go |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
my @arr = (47,85,25); | my @arr = (47,85,25); | Correct. | Perl |
String foo = 'hello'; | String foo = "hello"; | Double quotes. | Java |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
{{'id':'test'}} | {{"id":"test"}} | Use double quotes. | JSON |
let v=vec![47,2,68]; let first=&v[0]; v.push(64); | let mut v=vec![47,2,68]; let first=v[0]; v.push(64); | Copy instead of reference. | Rust |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<person age=14> | <person age="14"> | Quote attribute. | XML |
let s = String::from("message"); let borrow=&s; s.push_str("!"); | let mut s = String::from("message"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
print 'output' | print('output') | print needs parentheses. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
list[43] | if list.indices.contains(43) {{ list[43] }} | Check index. | Swift |
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