wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const person:Person = {{name:'value'}}; | const person:Person = {{name:'value', age:84}}; | Add missing property. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
for (int i=0; i<47; i++) {{}} | for (int i=0; i<47; i++) {{}} | Correct. | Java |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
if [ $bar = 36 ]; then | if [ "$bar" = 36 ]; then | Quote variable. | Shell |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
print 'data' | print('data') | print needs parentheses. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
item == '80' | item === 80 | Use strict equality. | JavaScript |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
SELECT id email FROM orders; | SELECT id, email FROM orders; | Add comma. | SQL |
object Product {{ def main(args: Array[String]) = println("test") }} | object Product {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
function bar() {{ echo 'value'; }} | function bar() {{ echo 'value'; }} | Correct. | PHP |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
foo = test | foo = 'test' | Quote strings. | Python |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
let vec=vec![100,14,10]; let head=&vec[0]; vec.push(61); | let mut vec=vec![100,14,10]; let head=vec[0]; vec.push(61); | Copy instead of reference. | Rust |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
20result = 10 | result20 = 10 | Variable cannot start with digit. | Python |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
list.forEach(function(x) {{ console.log(x); }}) | list.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(48); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(48); | Correct. | Node.js |
println('hello') | println("hello") | Double quotes. | Scala |
<p>test <b>hello</p></b> | <p>test <b>hello</b></p> | Nest properly. | HTML |
else
print('info') | else:
print('info') | Colon after else. | Python |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
class Item {{ int c; }}; | class Item {{ public: int c; }}; | Make public. | C++ |
if c = 55 | if c == 55 | Use ==. | Go |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
let z = 27; | let z = 27; | Correct. | JavaScript |
if bar = 93 | if bar == 93 | Use ==. | Ruby |
render | render() | Add parentheses. | Kotlin |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
DELETE FROM orders WHERE name=84 | DELETE FROM orders WHERE name=84; | Add semicolon. | SQL |
def baz():
print('hello') | def baz():
print('hello') | Indent function body. | Python |
data[83] | if (data.indices.contains(83)) data[83] | Check index. | Kotlin |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
<user><age>output</age><age>7</age></user | <user><age>output</age><age>7</age></user> | Add closing >. | XML |
let text = String::from("data"); let borrow=&text; text.push_str("!"); | let mut text = String::from("data"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (foo = 60) {{}} | if (foo == 60) {{}} | Use ==. | Kotlin |
INSERT INTO items VALUES ('test',56) | INSERT INTO items (age, role) VALUES ('test',56); | Specify columns. | SQL |
let a = 87; let a = 44; | let a = 87; a = 44; | Duplicate declaration. | JavaScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
{{"id":"test",}} | {{"id":"test"}} | Remove trailing comma. | JSON |
WHERE email = '36' | WHERE email = 36 | Don't quote integer. | SQL |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
function bar(x:string){{return x;}} bar(81); | function bar(x:string){{return x;}} bar('result'); | Pass correct type. | TypeScript |
// comment | /* comment */ | Use /* */. | CSS |
let mut num=55; let ref1=&mut num; let r2=&mut num; | let mut num=55; {{ let ref1=&mut num; }} let r2=&mut num; | Only one mutable borrow. | Rust |
if (foo = 58) | if (foo == 58) | Use ==. | C++ |
'test' + 42 | 'test' + str(42) | Can't add int to string. | Python |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
if (bar = 11) {} | if (bar == 11) {} | Use ==. | Dart |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
a = 84 | a=84 | No spaces. | Shell |
let result: number = 'message'; | let result: string = 'message'; | Fix type. | TypeScript |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
class Order {{ int val; }}
obj.val=5; | class Order {{ public int val; }}
obj.val=5; | Make field public. | Java |
echo 'test' | echo 'test'; | Add semicolon. | PHP |
compute | compute() | Add parentheses. | Swift |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
re.sqrt(82) | import re
re.sqrt(82) | Import module first. | Python |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
List(100,20,87) | List(100,20,87) | Correct. | Scala |
function handle(val)
print(val)
end | function handle(val)
print(val)
end | Correct. | Lua |
val data = 41; data = 47 | var data = 41; data = 47 | Use var for reassignment. | Scala |
if y = 77 {{}} | if y == 77 {{}} | Use ==. | Swift |
def bar
puts 'test'
end | def bar
puts 'test'
end | Correct. | Ruby |
if (z) console.log('yes') else console.log('no') | if (z) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
id: output
id: test, | id: output
id: test | Remove comma. | YAML |
if ($val = 69) | if ($val == 69) | Use ==. | Perl |
$temp = 20; if ($temp = 20) {{}} | $temp = 20; if ($temp == 20) {{}} | Use ==. | PHP |
var x = 22; | var x = 22; | Correct. | Dart |
var index int = 'world' | var index string = 'world' | Type mismatch. | Go |
def compute(a):
return a + 1 | def compute(a):
return a + 1 | Correct. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
<person age=62> | <person age="62"> | Quote attribute. | XML |
disp('info') | disp('info') | Correct. | MATLAB |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
def handle():
print('data') | def handle():
print('data') | Indent function body. | Python |
int bar = 'info'; | String bar = 'info'; | Type mismatch. | Dart |
let mut data=75; let r1=&mut data; let ref2=&mut data; | let mut data=75; {{ let r1=&mut data; }} let ref2=&mut data; | Only one mutable borrow. | Rust |
<ul><li>test<li>data</ul> | <ul><li>test</li><li>data</li></ul> | Close li. | HTML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if ($foo = 81) | if ($foo == 81) | Use ==. | Perl |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if temp > 81
print('value') | if temp > 81:
print('value') | Colon missing after if. | Python |
print 'output' | print 'output'; | Add semicolon. | Perl |
if (data = 52) | if (data == 52) | Use ==. | R |
'value' + 23 | 'value' + 23.to_s | Convert int. | Ruby |
List(82,3,25) | List(82,3,25) | Correct. | Scala |
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