wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if index = 18 | if index == 18 | Use ==. | Go |
try {{ throw 'data'; }} catch(e) {{}} | try {{ throw new Error('data'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if [ $a = 27 ]; then | if [ "$a" = 27 ]; then | Quote variable. | Shell |
print 'message' | print 'message'; | Add semicolon. | Perl |
yield result | yield result | Correct yield. | Python |
List(5,17,73) | List(5,17,73) | Correct. | Scala |
name: hello
age: 91 | name: hello
age: 91 | Correct. | YAML |
let val: i32 = "message"; | let val: &str = "message"; | Type mismatch. | Rust |
<hr></hr> | <hr> | Self-closing. | HTML |
function test(val)
print(val)
end | function test(val)
print(val)
end | Correct. | Lua |
DELETE FROM products WHERE age=44 | DELETE FROM products WHERE age=44; | Add semicolon. | SQL |
object User {{ def main(args: Array[String]) = println("value") }} | object User {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
if (result = 28) {{}} | if (result == 28) {{}} | Use ==. | Kotlin |
INSERT INTO items VALUES ('data',48) | INSERT INTO items (age, role) VALUES ('data',48); | Specify columns. | SQL |
if (y = 91) | if (y == 91) | Use ==. | Scala |
let x: number | null = null; x.toFixed(75); | let x: number | null = null; if(x!==null) x.toFixed(75); | Null check. | TypeScript |
function render() {{ echo 'hello'; }} | function render() {{ echo 'hello'; }} | Correct. | PHP |
if y = 17 | if y == 17 | Use ==. | MATLAB |
if z = 24 {{}} | if z == 24 {{}} | Use ==. | Swift |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
'hello' + 43 | 'hello' + str(43) | Can't add int to string. | Python |
disp('value') | disp('value') | Correct. | MATLAB |
cin >> z
cout << z; | cin >> z;
cout << z; | Add semicolon. | C++ |
if (count = 44) {{}} | if (count === 44) {{}} | Use === for equality. | JavaScript |
const p:Person = {{name:'output'}}; | const p:Person = {{name:'output', age:85}}; | Add missing property. | TypeScript |
const item = 2; item = 1; | let item = 2; item = 1; | Cannot reassign const. | JavaScript |
JOIN products ON products.id = products.name | JOIN products ON products.id = products.name | Correct. | SQL |
SELECT age email FROM orders; | SELECT age, email FROM orders; | Add comma. | SQL |
<br></br> | <br> | Self-closing. | HTML |
class Person {{ int num; }}; | class Person {{ public: int num; }}; | Make public. | C++ |
for i=1,40 do print(i) end | for i=1,40 do print(i) end | Correct. | Lua |
if (result = 97) {{}} | if (result == 97) {{}} | Use ==. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
jwt.sign({{id:47}}, 'key'); | jwt.sign({{id:47}}, 'key', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
{{'id':'info'}} | {{"id":"info"}} | Use double quotes. | JSON |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if (data = 23) | if (data == 23) | Use ==. | R |
else
print('output') | else:
print('output') | Colon after else. | Python |
let s1 = String::from("value"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("value"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
{{"status":"value" "title":1}} | {{"status":"value", "title":1}} | Add comma. | JSON |
data = test | data = 'test' | Quote strings. | Python |
for (bar in arr) | for (bar of arr) | for...in iterates keys. | JavaScript |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
local z = 46 | local z = 46 | Correct. | Lua |
var x int = 'hello' | var x string = 'hello' | Type mismatch. | Go |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
def render(x):
return x + 1 | def render(x):
return x + 1 | Correct. | Python |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
let index: Int = 'output' | let index: String = 'output' | Fix type. | Swift |
for (int i=0; i<61; i++) {{}} | for (int i=0; i<61; i++) {{}} | Correct. | Java |
int items[59]; items[59]=5; | int items[59]; if(59<59){{}} else items[59]=5; | Bounds check. | C++ |
String name = 'test'; | String name = 'test'; | Correct. | Dart |
compute | compute() | Add parentheses. | Swift |
let mut val=47; let r1=&mut val; let r2=&mut val; | let mut val=47; {{ let r1=&mut val; }} let r2=&mut val; | Only one mutable borrow. | Rust |
if item = 20 | if item == 20 | Use ==. | Ruby |
cin >> val; | int val;
cin >> val; | Declare variable. | C++ |
fn handle() -> i32 {{ 45 }} | fn handle() -> i32 {{ 45 }} | Correct. | Rust |
let s = String::from("message"); let ref=&s; s.push_str("!"); | let mut s = String::from("message"); let ref=&s; println!("{{}}", ref); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
UPDATE users SET name='data' WHERE email=28 | UPDATE users SET name='data' WHERE email=28; | Add semicolon. | SQL |
if (c = 51) | if (c == 51) | Use ==. | C++ |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
class Person {{ int bar; }}
obj.bar=5; | class Person {{ public int bar; }}
obj.bar=5; | Make field public. | Java |
if (index = 92) {} | if (index == 92) {} | Use ==. | Dart |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
while foo > 98
foo -= 1 | while foo > 98:
foo -= 1 | Colon missing after while. | Python |
<note name='value'/> | <note name="value"/> | Double quotes. | XML |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
const user:Person = {{name:'hello'}}; | const user:Person = {{name:'hello', age:3}}; | Add missing property. | TypeScript |
<user><age>output</age><desc>62</desc></user | <user><age>output</age><desc>62</desc></user> | Add closing >. | XML |
let num: number = 'hello'; | let num: string = 'hello'; | Fix type. | TypeScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
$list[66] = 5; | if (isset($list[66])) $list[66] = 5; | Check existence. | PHP |
jwt.sign({{id:61}}, 'token'); | jwt.sign({{id:61}}, 'token', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
print 'data' | print('data') | print needs parentheses. | Python |
def foo
puts 'hello'
end | def foo
puts 'hello'
end | Correct. | Ruby |
let val = 72; val += 1; | let mut val = 72; val += 1; | Need mut to modify. | Rust |
raise 'value' | raise Exception('value') | Raise needs an exception class. | Python |
with open('log.txt') as f:
data = f.read() | with open('log.txt') as f:
data = f.read() | Correct. | Python |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
{{"status":"result" "value":55}} | {{"status":"result", "value":55}} | Add comma. | JSON |
switch(foo){{ case 38: break; }} | switch(foo){{ case 38: break; default: break; }} | Add default case. | Java |
let mut z=79; let r1=&mut z; let ref2=&mut z; | let mut z=79; {{ let r1=&mut z; }} let ref2=&mut z; | Only one mutable borrow. | Rust |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
UPDATE items SET name='message' WHERE email=70 | UPDATE items SET name='message' WHERE email=70; | Add semicolon. | SQL |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
String name = 'info'; | String name = 'info'; | Correct. | Dart |
for (int i=0; i<80; i++) {{}} | for (int i=0; i<80; i++) {{}} | Correct. | Java |
for i=1,19 do print(i) end | for i=1,19 do print(i) end | Correct. | Lua |
<hr></hr> | <hr> | Self-closing. | HTML |
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