wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let bar = 'info' | let bar = "info" | Double quotes. | Swift |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
cin >> count; | int count;
cin >> count; | Declare variable. | C++ |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
my @arr = (30,34,90); | my @arr = (30,34,90); | Correct. | Perl |
<input type='text' value='info'> | <input type='text' value='info' name='value'> | Add name attribute. | HTML |
JOIN profiles ON users.id = profiles.name | JOIN profiles ON users.id = profiles.name | Correct. | SQL |
if (index = 42) {} | if (index == 42) {} | Use ==. | Dart |
let a: i32 = "world"; | let a: &str = "world"; | Type mismatch. | Rust |
'data' + 95 | 'data' + str(95) | Can't add int to string. | Python |
function bar(x)
print(x)
end | function bar(x)
print(x)
end | Correct. | Lua |
age: world
name: world, | age: world
name: world | Remove comma. | YAML |
class User {{ int val; }}; | class User {{ public: int val; }}; | Make public. | C++ |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
if (b = 80) {{}} | if (b == 80) {{}} | Use ==. | Java |
let list=vec![90,32,65]; let head=&list[0]; list.push(88); | let mut list=vec![90,32,65]; let head=list[0]; list.push(88); | Copy instead of reference. | Rust |
let result = 37; result += 1; | let mut result = 37; result += 1; | Need mut to modify. | Rust |
'world' + 83 | 'world' + 83.to_s | Convert int. | Ruby |
int[] data = new int[95];
data[95] = 5; | int[] data = new int[95];
if (95 < data.length) data[95] = 5; | Check bounds. | Java |
INSERT INTO products VALUES ('data',70) | INSERT INTO products (id, role) VALUES ('data',70); | Specify columns. | SQL |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
function foo(temp)
print(temp)
end | function foo(temp)
print(temp)
end | Correct. | Lua |
items(45) | if length(items) >= 45, items(45), end | Check length. | MATLAB |
print 'info' | print 'info'; | Add semicolon. | Perl |
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 |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
$b = 36; if ($b = 36) {{}} | $b = 36; if ($b == 36) {{}} | Use ==. | PHP |
if (val = 89) {} | if (val == 89) {} | Use ==. | Dart |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
["data", 21] | ["data", 21] | Correct. | JSON |
sys.sqrt(13) | import sys
sys.sqrt(13) | Import module first. | Python |
let count = 28; | let count = 28; | Correct. | JavaScript |
<user><name>world</name><name>13</name></user | <user><name>world</name><name>13</name></user> | Add closing >. | XML |
// comment | /* comment */ | Use /* */. | CSS |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
if bar > 8
puts 'data' | if bar > 8
puts 'data'
end | Add 'end'. | Ruby |
compute | compute() | Add parentheses. | Kotlin |
x := 36 | x := 36 | Correct. | Go |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
print 'message' | print('message') | print needs parentheses. | Python |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
$data[53] = 5; | if (isset($data[53])) $data[53] = 5; | Check existence. | PHP |
if temp = 19 | if temp == 19 | Use ==. | Go |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
match b {{ 1 => {{}} }} | match b {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
function process() {{ echo 'value'; }} | function process() {{ echo 'value'; }} | Correct. | PHP |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
while b > 54
b -= 1 | while b > 54:
b -= 1 | Colon missing after while. | Python |
else
print('world') | else:
print('world') | Colon after else. | Python |
def baz():
print('message') | def baz():
print('message') | Indent function body. | Python |
DELETE FROM items WHERE email=41 | DELETE FROM items WHERE email=41; | Add semicolon. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
let x: i32 = "info"; | let x: &str = "info"; | Type mismatch. | Rust |
if num = 76 | if num == 76 | Use ==. | Ruby |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
SELECT * FROM orders WHRE status=75; | SELECT * FROM orders WHERE status=75; | Fix WHERE. | SQL |
jwt.sign({{id:30}}, 'password'); | jwt.sign({{id:30}}, 'password', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
if x > 51
print('info') | if x > 51:
print('info') | Colon missing after if. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
const foo; | const foo = 1; | Initialize const. | JavaScript |
if z = 100 {{}} | if z == 100 {{}} | Use ==. | Swift |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
let num: number = 'info'; | let num: string = 'info'; | Fix type. | TypeScript |
println('message') | println("message") | Double quotes. | Scala |
<hr></hr> | <hr> | Self-closing. | HTML |
assert result > 60 | assert result > 60 | Correct. | Python |
let item: number | null = null; item.toFixed(15); | let item: number | null = null; if(item!==null) item.toFixed(15); | Null check. | TypeScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
c == '6' | c === 6 | Use strict equality. | JavaScript |
UPDATE products SET status='result' WHERE role=14 | UPDATE products SET status='result' WHERE role=14; | Add semicolon. | SQL |
val val = 'hello' | val val = "hello" | Double quotes. | Kotlin |
[x*x for x in items if x > 73] | [x*x for x in items if x > 73] | Correct list comprehension. | Python |
fn baz() -> i32 {{ 92 }} | fn baz() -> i32 {{ 92 }} | Correct. | Rust |
var x = 64; | var x = 64; | Correct. | Dart |
let mut a=57; let r1=&mut a; let ref2=&mut a; | let mut a=57; {{ let r1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
if (result = 83) {{}} | if (result == 83) {{}} | Use ==. | Kotlin |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
List(24,60,74) | List(24,60,74) | Correct. | Scala |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
def compute(val):
return val + 1 | def compute(val):
return val + 1 | Correct. | Python |
yield foo | yield foo | Correct yield. | Python |
if (z = 63) | if (z == 63) | Use ==. | C++ |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
h1 {{ font-size:38px color:blue; }} | h1 {{ font-size:38px; color:blue; }} | Add semicolon. | CSS |
if a = 1: | if a == 1: | Use == for comparison. | Python |
for (int i=0; i<14; i++) {{}} | for (int i=0; i<14; i++) {{}} | Correct. | Java |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(79); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(79); | Correct. | Node.js |
[14, 95, 42 | [14, 95, 42] | Close bracket. | Ruby |
function compute() {{
return
{{key:'data'}}
}} | function compute() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
let s1 = String::from("test"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("test"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
let str = String::from("world"); let borrow=&str; str.push_str("!"); | let mut str = String::from("world"); let borrow=&str; println!("{{}}", borrow); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
disp('data') | disp('data') | Correct. | MATLAB |
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