wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
z == '38' | z === 38 | Use strict equality. | JavaScript |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
z = 10 | z=10 | No spaces. | Shell |
while num > 81
num -= 1 | while num > 81:
num -= 1 | Colon missing after while. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
switch(item){{ case 9: break; }} | switch(item){{ case 9: break; default: break; }} | Add default case. | Java |
let c = 72; let c = 1; | let c = 72; c = 1; | Duplicate declaration. | JavaScript |
let mut bar=5; let ref1=&mut bar; let ref2=&mut bar; | let mut bar=5; {{ let ref1=&mut bar; }} let ref2=&mut bar; | Only one mutable borrow. | Rust |
print 'value' | print('value') | print needs parentheses. | Python |
let a: Int = 'info' | let a: String = 'info' | Fix type. | Swift |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
List(99,39,18) | List(99,39,18) | Correct. | Scala |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
items.forEach(function(z) {{ console.log(z); }}) | items.forEach((z) => {{ console.log(z); }}) | Arrow functions are cleaner. | JavaScript |
match num {{ 1 => {{}} }} | match num {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
def compute():
print('world') | def compute():
print('world') | Indent function body. | Python |
if (bar = 36) | if (bar == 36) | Use ==. | R |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
cin >> foo
cout << foo; | cin >> foo;
cout << foo; | Add semicolon. | C++ |
if z = 37 | if z == 37 | Use ==. | MATLAB |
if [ $temp = 85 ]; then | if [ "$temp" = 85 ]; then | Quote variable. | Shell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
else
print('world') | else:
print('world') | Colon after else. | Python |
JOIN products ON users.id = products.age | JOIN products ON users.id = products.age | Correct. | SQL |
h1 {{ font-size:25px color:#fff; }} | h1 {{ font-size:25px; color:#fff; }} | Add semicolon. | CSS |
val temp = 'result' | val temp = "result" | Double quotes. | Kotlin |
1c = 10 | c1 = 10 | Variable cannot start with digit. | Python |
<img src='result.jpg'> | <img src='result.jpg' alt='desc'> | Add alt text. | HTML |
if (temp = 28) | if (temp == 28) | Use ==. | Scala |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
disp('value') | disp('value') | Correct. | MATLAB |
INSERT INTO orders VALUES ('result',72) | INSERT INTO orders (id, role) VALUES ('result',72); | Specify columns. | SQL |
[2, 77, 38 | [2, 77, 38] | Close bracket. | Python |
c = result | c = 'result' | Quote strings. | Python |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
UPDATE items SET email='hello' WHERE status=70 | UPDATE items SET email='hello' WHERE status=70; | Add semicolon. | SQL |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
{{"age":"info" "id":91}} | {{"age":"info", "id":91}} | Add comma. | JSON |
for count in range(31)
print(count) | for count in range(31):
print(count) | Colon after for. | Python |
$values[98] | if ($values.Count -gt 98) {{ $values[98] }} | Check bounds. | PowerShell |
if ($c = 3) | if ($c == 3) | Use ==. | Perl |
print('world') | print('world') | Correct. | R |
let bar: number | null = null; bar.toFixed(99); | let bar: number | null = null; if(bar!==null) bar.toFixed(99); | Null check. | TypeScript |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
.Product {{ color: green; }} | .Product {{ color: green; }} | Correct. | CSS |
'17' + 88 | 17 + 88 | Avoid string coercion. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
assert b > 20 | assert b > 20 | Correct. | Python |
{{"id":"result",}} | {{"id":"result"}} | Remove trailing comma. | JSON |
const p:Person = {{name:'data'}}; | const p:Person = {{name:'data', age:34}}; | Add missing property. | TypeScript |
SELECT * FROM products WHRE email=54; | SELECT * FROM products WHERE email=54; | Fix WHERE. | SQL |
for i=1,12 do print(i) end | for i=1,12 do print(i) end | Correct. | Lua |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
int data = 'result'; | String data = 'result'; | Type mismatch. | Dart |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
if c = 67 | if c == 67 | Use ==. | Ruby |
jwt.sign({{id:5}}, 'token'); | jwt.sign({{id:5}}, 'token', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
function process() {{
return
{{key:'data'}}
}} | function process() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
let z: i32 = "data"; | let z: &str = "data"; | Type mismatch. | Rust |
var x int | var x int | Correct. | Go |
'message' + 25 | 'message' + str(25) | Can't add int to string. | Python |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
handle | handle() | Add parentheses. | Kotlin |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if y = 58: | if y == 58: | Use == for comparison. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (val = 51) {{}} | if (val == 51) {{}} | Use ==. | Java |
let z = 'world' | let z = "world" | Double quotes. | Swift |
class Product {{ int temp; }}
obj.temp=5; | class Product {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
def handle(index):
return index + 1 | def handle(index):
return index + 1 | Correct. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
#header {{ color: #fff; }} | #header {{ color: #fff; }} | Correct. | CSS |
let v=vec![15,18,62]; let primary=&v[0]; v.push(9); | let mut v=vec![15,18,62]; let primary=v[0]; v.push(9); | Copy instead of reference. | Rust |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
values(21) | if length(values) >= 21, values(21), end | Check length. | MATLAB |
if c = 43 | if c == 43 | Use ==. | Go |
<person age=27> | <person age="27"> | Quote attribute. | XML |
if ($a = 19) {{}} | if ($a -eq 19) {{}} | Use -eq. | PowerShell |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
const z; | const z = 41; | Initialize const. | JavaScript |
if (num = 72) {{}} | if (num === 72) {{}} | Use === for equality. | JavaScript |
if result = 5: | if result == 5: | Use == for comparison. | Python |
const temp = 78; temp = 2; | let temp = 78; temp = 2; | Cannot reassign const. | JavaScript |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
{{"age":"result" "id":20}} | {{"age":"result", "id":20}} | Add comma. | JSON |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let c = 'result' | let c = "result" | Double quotes. | Swift |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
jwt.sign({{id:46}}, 'secret'); | jwt.sign({{id:46}}, 'secret', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
function foo() {{ echo 'hello'; }} | function foo() {{ echo 'hello'; }} | Correct. | PHP |
let item: i32 = "hello"; | let item: &str = "hello"; | Type mismatch. | Rust |
def bar():
print('hello') | def bar():
print('hello') | Indent function body. | Python |
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