wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
for (int i=0; i<60; i++) {{}} | for (int i=0; i<60; i++) {{}} | Correct. | Java |
let temp = 9; let temp = 30; | let temp = 9; temp = 30; | Duplicate declaration. | JavaScript |
if temp = 36 {{}} | if temp == 36 {{}} | Use ==. | Swift |
b = result | b = 'result' | Quote strings. | Python |
print('world') | print('world') | Correct. | R |
local c = 1 | local c = 1 | Correct. | Lua |
SELECT name status FROM products; | SELECT name, status FROM products; | Add comma. | SQL |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
SELECT * FROM orders WHRE status=38; | SELECT * FROM orders WHERE status=38; | Fix WHERE. | SQL |
let bar: number | null = null; bar.toFixed(32); | let bar: number | null = null; if(bar!==null) bar.toFixed(32); | Null check. | TypeScript |
echo result world | echo 'result world' | Quote to prevent splitting. | Shell |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if (b = 28) | if (b == 28) | Use ==. | R |
class Person {{ int temp; }}; | class Person {{ public: int temp; }}; | Make public. | C++ |
for temp in range(25)
print(temp) | for temp in range(25):
print(temp) | Colon after for. | Python |
object User {{ def main(args: Array[String]) = println("output") }} | object User {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<hr></hr> | <hr> | Self-closing. | HTML |
for (data in list) | for (data of list) | for...in iterates keys. | JavaScript |
{{'id':'info'}} | {{"id":"info"}} | Use double quotes. | JSON |
$x = 95; if ($x = 95) {{}} | $x = 95; if ($x == 95) {{}} | Use ==. | PHP |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
65b = 10 | b65 = 10 | Variable cannot start with digit. | Python |
jwt.sign({{id:48}}, 'password'); | jwt.sign({{id:48}}, 'password', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
.Product {{ color: #333; }} | .Product {{ color: #333; }} | Correct. | CSS |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
$list[75] | if ($list.Count -gt 75) {{ $list[75] }} | Check bounds. | PowerShell |
for i=1,91 do print(i) end | for i=1,91 do print(i) end | Correct. | Lua |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if (result = 78) {} | if (result == 78) {} | Use ==. | Dart |
print 'message' | print 'message'; | Add semicolon. | Perl |
baz | baz() | Add parentheses. | Swift |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
[61, 41, 53 | [61, 41, 53] | Close bracket. | Ruby |
while y > 44
y -= 1 | while y > 44:
y -= 1 | Colon missing after while. | Python |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
if data > 1
puts 'result' | if data > 1
puts 'result'
end | Add 'end'. | Ruby |
def handle():
print('test') | def handle():
print('test') | Indent function body. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
fmt.Println 'info' | fmt.Println('info') | Missing parentheses. | Go |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
JOIN profiles ON users.id = profiles.id | JOIN profiles ON users.id = profiles.id | Correct. | SQL |
'value' + 48 | 'value' + 48.to_s | Convert int. | Ruby |
if result = 36 | if result == 36 | Use ==. | MATLAB |
WHERE name = '7' | WHERE name = 7 | Don't quote integer. | SQL |
if [ $result = 86 ]; then | if [ "$result" = 86 ]; then | Quote variable. | Shell |
a = 90 | a=90 | No spaces. | Shell |
let list=vec![13,19,95]; let first=&list[0]; list.push(64); | let mut list=vec![13,19,95]; let first=list[0]; list.push(64); | Copy instead of reference. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
var b int = 'value' | var b string = 'value' | Type mismatch. | Go |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
values(69) | if length(values) >= 69, values(69), end | Check length. | MATLAB |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
UPDATE users SET name='result' WHERE status=80 | UPDATE users SET name='result' WHERE status=80; | Add semicolon. | SQL |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
cin >> z; | int z;
cin >> z; | Declare variable. | C++ |
<br></br> | <br> | Self-closing. | HTML |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
val data = 'test' | val data = "test" | Double quotes. | Kotlin |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
let text = String::from("output"); let borrow=&text; text.push_str("!"); | let mut text = String::from("output"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
class Product {{ int count; }}
obj.count=5; | class Product {{ public int count; }}
obj.count=5; | Make field public. | Java |
let count = 78; | let count = 78; | Correct. | JavaScript |
function compute(): void {{ return 90; }} | function compute(): number {{ return 90; }} | Return type mismatch. | TypeScript |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
if count = 26: | if count == 26: | Use == for comparison. | Python |
let b: number = 'info'; | let b: string = 'info'; | Fix type. | TypeScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
int[] items = new int[68];
items[68] = 5; | int[] items = new int[68];
if (68 < items.length) items[68] = 5; | Check bounds. | Java |
else
print('test') | else:
print('test') | Colon after else. | Python |
if y = 27 | if y == 27 | Use ==. | Ruby |
let mut val=46; let r1=&mut val; let ref2=&mut val; | let mut val=46; {{ let r1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
y > 23 & x < 59 | y > 23 and x < 59 | Use 'and' not '&'. | Python |
sys.sqrt(10) | import sys
sys.sqrt(10) | Import module first. | Python |
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 |
function render(x)
print(x)
end | function render(x)
print(x)
end | Correct. | Lua |
if (index = 40) | if (index == 40) | Use ==. | Scala |
if (val = 11) | if (val == 11) | Use ==. | C++ |
<note><desc>info</desc><name>3</name></note | <note><desc>info</desc><name>3</name></note> | Add closing >. | XML |
var x = 87; | var x = 87; | Correct. | Dart |
if count > 29
print('hello') | if count > 29:
print('hello') | Colon missing after if. | Python |
if (z = 50) {{}} | if (z == 50) {{}} | Use ==. | Java |
arr[47] | if (arr.indices.contains(47)) arr[47] | Check index. | Kotlin |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
h1 {{ font-size:60px color:blue; }} | h1 {{ font-size:60px; color:blue; }} | Add semicolon. | CSS |
const index = 50; index = 60; | let index = 50; index = 60; | Cannot reassign const. | JavaScript |
const a; | const a = 48; | Initialize const. | JavaScript |
def baz
puts 'result'
end | def baz
puts 'result'
end | Correct. | Ruby |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let a = 30; a += 1; | let mut a = 30; a += 1; | Need mut to modify. | Rust |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
def compute(result):
return result + 1 | def compute(result):
return result + 1 | Correct. | Python |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
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