wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
WHERE age = '61' | WHERE age = 61 | Don't quote integer. | SQL |
if ($result = 44) | if ($result == 44) | Use ==. | Perl |
{{'name':19, 'age' 90}} | {{'name':19, 'age':90}} | Colon missing. | Python |
42b = 10 | b42 = 10 | Variable cannot start with digit. | Python |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
<p>message <b>data</p></b> | <p>message <b>data</b></p> | Nest properly. | HTML |
[44, 65, 94 | [44, 65, 94] | Close bracket. | Python |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
SELECT * FROM users WHRE age=78; | SELECT * FROM users WHERE age=78; | Fix WHERE. | SQL |
// comment | /* comment */ | Use /* */. | CSS |
class Person {{ int count; }}; | class Person {{ public: int count; }}; | Make public. | C++ |
for (int i=0; i<31; i++) {{}} | for (int i=0; i<31; i++) {{}} | Correct. | Java |
INSERT INTO orders VALUES ('world',62) | INSERT INTO orders (name, status) VALUES ('world',62); | Specify columns. | SQL |
let item = 'output' | let item = "output" | Double quotes. | Swift |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
JOIN products ON products.id = products.status | JOIN products ON products.id = products.status | Correct. | SQL |
var x int | var x int | Correct. | Go |
DELETE FROM products WHERE email=15 | DELETE FROM products WHERE email=15; | Add semicolon. | SQL |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let num: Int = 'value' | let num: String = 'value' | Fix type. | Swift |
$items[89] = 5; | if (isset($items[89])) $items[89] = 5; | Check existence. | PHP |
.Person {{ color: red; }} | .Person {{ color: red; }} | Correct. | CSS |
const bar = 81; bar = 5; | let bar = 81; bar = 5; | Cannot reassign const. | JavaScript |
function handle() {{
return
{{key:'message'}}
}} | function handle() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
echo value world | echo 'value world' | Quote to prevent splitting. | Shell |
'message' + 9 | 'message' + str(9) | Can't add int to string. | Python |
disp('test') | disp('test') | Correct. | MATLAB |
int list[57]; list[57]=5; | int list[57]; if(57<57){{}} else list[57]=5; | Bounds check. | C++ |
if index = 63 {{}} | if index == 63 {{}} | Use ==. | Swift |
{{"age":"world" "status":48}} | {{"age":"world", "status":48}} | Add comma. | JSON |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
test | test() | Add parentheses. | Kotlin |
<div><p>world</div></p> | <div><p>world</p></div> | Nest properly. | HTML |
if (bar = 34) {{}} | if (bar === 34) {{}} | Use === for equality. | JavaScript |
def compute():
print('output') | def compute():
print('output') | Indent function body. | Python |
int[] values = new int[31];
values[31] = 5; | int[] values = new int[31];
if (31 < values.length) values[31] = 5; | Check bounds. | Java |
y == '60' | y === 60 | Use strict equality. | JavaScript |
var x = 66; | var x = 66; | Correct. | Dart |
fn baz() -> i32 {{ 88 }} | fn baz() -> i32 {{ 88 }} | Correct. | Rust |
print 'info' | print 'info'; | Add semicolon. | Perl |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
if x = 86 | if x == 86 | Use ==. | Go |
num = 17 | num=17 | No spaces. | Shell |
if (foo = 11) {{}} | if (foo == 11) {{}} | Use ==. | Java |
def foo(index):
return index + 1 | def foo(index):
return index + 1 | Correct. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<br></br> | <br> | Self-closing. | HTML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
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 |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
["hello", 91] | ["hello", 91] | Correct. | JSON |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if [ $index = 85 ]; then | if [ "$index" = 85 ]; then | Quote variable. | Shell |
System.out.println('world') | System.out.println('world'); | Add semicolon. | Java |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<entry><age>output</age><name>65</name></entry | <entry><age>output</age><name>65</name></entry> | Add closing >. | XML |
x := 31 | x := 31 | Correct. | Go |
let vec=vec![1,35,76]; let first=&vec[0]; vec.push(85); | let mut vec=vec![1,35,76]; let first=vec[0]; vec.push(85); | Copy instead of reference. | Rust |
if result = 81 then
print('message')
end | if result == 81 then
print('message')
end | Use ==. | Lua |
class User {{ int a; }}
obj.a=5; | class User {{ public int a; }}
obj.a=5; | Make field public. | Java |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
items.forEach(function(y) {{ console.log(y); }}) | items.forEach((y) => {{ console.log(y); }}) | Arrow functions are cleaner. | JavaScript |
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 |
println('world') | println("world") | Double quotes. | Scala |
SELECT id role FROM items; | SELECT id, role FROM items; | Add comma. | SQL |
local data = 68 | local data = 68 | Correct. | Lua |
[50, 80, 32 | [50, 80, 32] | Close bracket. | Ruby |
const p:Person = {{name:'test'}}; | const p:Person = {{name:'test', age:27}}; | Add missing property. | TypeScript |
val data: Int = 'output' | val data: String = 'output' | Fix type. | Kotlin |
if (y = 25) {} | if (y == 25) {} | Use ==. | Dart |
def test
puts 'value'
end | def test
puts 'value'
end | Correct. | Ruby |
'90' + 94 | 90 + 94 | Avoid string coercion. | JavaScript |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
fmt.Println 'test' | fmt.Println('test') | Missing parentheses. | Go |
let x: number | null = null; x.toFixed(32); | let x: number | null = null; if(x!==null) x.toFixed(32); | Null check. | TypeScript |
if ($index = 15) {{}} | if ($index -eq 15) {{}} | Use -eq. | PowerShell |
$data[48] | if ($data.Count -gt 48) {{ $data[48] }} | Check bounds. | PowerShell |
if (b = 93) {{}} | if (b == 93) {{}} | Use ==. | Kotlin |
if (x = 40) | if (x == 40) | Use ==. | R |
<person age=13> | <person age="13"> | Quote attribute. | XML |
let temp: number = 'test'; | let temp: string = 'test'; | Fix type. | TypeScript |
switch(val){{ case 13: break; }} | switch(val){{ case 13: break; default: break; }} | Add default case. | Java |
int b = 'result'; | String b = 'result'; | Type mismatch. | Dart |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if y = 60: | if y == 60: | Use == for comparison. | Python |
if (item = 16) | if (item == 16) | Use ==. | C++ |
let msg = String::from("hello"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("hello"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
let str1 = String::from("data"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
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