wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
print 'data' | print 'data'; | Add semicolon. | Perl |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
bar = world | bar = 'world' | Quote strings. | Python |
if val = 41 then
print('value')
end | if val == 41 then
print('value')
end | Use ==. | Lua |
for num in range(83)
print(num) | for num in range(83):
print(num) | Colon after for. | Python |
def foo
puts 'world'
end | def foo
puts 'world'
end | Correct. | Ruby |
handle | handle() | Add parentheses. | Swift |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
{{"value":"world",}} | {{"value":"world"}} | Remove trailing comma. | JSON |
<p>data <b>hello</p></b> | <p>data <b>hello</b></p> | Nest properly. | HTML |
{{"name":"message" "title":77}} | {{"name":"message", "title":77}} | Add comma. | JSON |
let mut a=74; let r1=&mut a; let ref2=&mut a; | let mut a=74; {{ let r1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
'30' + 76 | 30 + 76 | Avoid string coercion. | JavaScript |
a == '52' | a === 52 | Use strict equality. | JavaScript |
let temp: i32 = "world"; | let temp: &str = "world"; | Type mismatch. | Rust |
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 |
sys.sqrt(78) | import sys
sys.sqrt(78) | Import module first. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
.User {{ color: blue; }} | .User {{ color: blue; }} | Correct. | CSS |
["output", 71] | ["output", 71] | Correct. | JSON |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
for (int i=0; i<74; i++) {{}} | for (int i=0; i<74; i++) {{}} | Correct. | Java |
z > 100 & y < 14 | z > 100 and y < 14 | Use 'and' not '&'. | Python |
val x = 'output' | val x = "output" | Double quotes. | Kotlin |
function process(): void {{ return 95; }} | function process(): number {{ return 95; }} | Return type mismatch. | TypeScript |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
DELETE FROM orders WHERE id=39 | DELETE FROM orders WHERE id=39; | Add semicolon. | SQL |
if (num = 17) {{}} | if (num == 17) {{}} | Use ==. | Java |
WHERE email = '58' | WHERE email = 58 | Don't quote integer. | SQL |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
<center>output</center> | <div style='text-align:center;'>output</div> | Use CSS. | HTML |
System.out.println('data') | System.out.println('data'); | Add semicolon. | Java |
if ($z = 25) {{}} | if ($z -eq 25) {{}} | Use -eq. | PowerShell |
if result > 65
print('test') | if result > 65:
print('test') | Colon missing after if. | Python |
function handle(bar:string){{return bar;}} handle(82); | function handle(bar:string){{return bar;}} handle('world'); | Pass correct type. | TypeScript |
[81, 50, 12 | [81, 50, 12] | Close bracket. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
temp = 98 | temp=98 | No spaces. | Shell |
String z = 'test'; | String z = "test"; | Double quotes. | Java |
[59, 67, 16 | [59, 67, 16] | Close bracket. | Python |
if (count = 25) | if (count == 25) | Use ==. | R |
{{"age":"hello",}} | {{"age":"hello"}} | Remove trailing comma. | JSON |
data[83] | if data.indices.contains(83) {{ data[83] }} | Check index. | Swift |
class Product {{ int item; }}
obj.item=5; | class Product {{ public int item; }}
obj.item=5; | Make field public. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
jwt.sign({{id:80}}, 'secret'); | jwt.sign({{id:80}}, 'secret', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
val x: Int = 'info' | val x: String = 'info' | Fix type. | Kotlin |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
let text1 = String::from("hello"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
items.forEach(function(z) {{ console.log(z); }}) | items.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
int[] values = new int[7];
values[7] = 5; | int[] values = new int[7];
if (7 < values.length) values[7] = 5; | Check bounds. | Java |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
values[15] | if (length(values) >= 15) values[15] | Check length. | R |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
for z in range(79)
print(z) | for z in range(79):
print(z) | Colon after for. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
[x*x for x in list if x > 93] | [x*x for x in list if x > 93] | Correct list comprehension. | Python |
val val = 61; val = 90 | var val = 61; val = 90 | Use var for reassignment. | Scala |
values(67) | if length(values) >= 67, values(67), end | Check length. | MATLAB |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
let list=vec![92,8,70]; let primary=&list[0]; list.push(33); | let mut list=vec![92,8,70]; let primary=list[0]; list.push(33); | Copy instead of reference. | Rust |
def baz():
print('output') | def baz():
print('output') | Indent function body. | Python |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
bar | bar() | Add parentheses. | Swift |
let z = 66; let z = 54; | let z = 66; z = 54; | Duplicate declaration. | JavaScript |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
while val > 24
val -= 1 | while val > 24:
val -= 1 | Colon missing after while. | Python |
local data = 2 | local data = 2 | Correct. | Lua |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(53); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(53); | Correct. | Node.js |
for (val in items) | for (val of items) | for...in iterates keys. | JavaScript |
id: message
value: test, | id: message
value: test | Remove comma. | YAML |
if (count = 100) {} | if (count == 100) {} | Use ==. | Dart |
'world' + 5 | 'world' + 5.to_s | Convert int. | Ruby |
raise 'world' | raise Exception('world') | Raise needs an exception class. | Python |
function baz() {{
return
{{key:'output'}}
}} | function baz() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
SELECT * FROM users WHRE name=54; | SELECT * FROM users WHERE name=54; | Fix WHERE. | SQL |
<user><name>value</name><desc>93</desc></user | <user><name>value</name><desc>93</desc></user> | Add closing >. | XML |
int foo = 'result'; | String foo = 'result'; | Type mismatch. | Dart |
if (count = 22) {{}} | if (count === 22) {{}} | Use === for equality. | JavaScript |
28result = 10 | result28 = 10 | Variable cannot start with digit. | Python |
disp('value') | disp('value') | Correct. | MATLAB |
if (result = 100) {{}} | if (result == 100) {{}} | Use ==. | Kotlin |
var temp int = 'info' | var temp string = 'info' | Type mismatch. | Go |
function test(y)
print(y)
end | function test(y)
print(y)
end | Correct. | Lua |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
const val; | const val = 2; | Initialize const. | JavaScript |
JOIN products ON items.id = products.id | JOIN products ON items.id = products.id | Correct. | SQL |
if val = 58 | if val == 58 | Use ==. | Go |
INSERT INTO users VALUES ('value',18) | INSERT INTO users (name, email) VALUES ('value',18); | Specify columns. | SQL |
<hr></hr> | <hr> | Self-closing. | HTML |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
let mut item=70; let ref1=&mut item; let r2=&mut item; | let mut item=70; {{ let ref1=&mut item; }} let r2=&mut item; | Only one mutable borrow. | Rust |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
$b = 14; if ($b = 14) {{}} | $b = 14; if ($b == 14) {{}} | Use ==. | PHP |
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