wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
if index = 13 | if index == 13 | Use ==. | Ruby |
<entry><desc>hello</desc><desc>79</desc></entry | <entry><desc>hello</desc><desc>79</desc></entry> | Add closing >. | XML |
int data = 'data'; | String data = 'data'; | Type mismatch. | Dart |
["test", 85] | ["test", 85] | Correct. | JSON |
class Item {{ int b; }}
obj.b=5; | class Item {{ public int b; }}
obj.b=5; | Make field public. | Java |
WHERE email = '51' | WHERE email = 51 | Don't quote integer. | SQL |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
let b = 51; | let b = 51; | Correct. | JavaScript |
println('hello') | println("hello") | Double quotes. | Scala |
let v=vec![70,4,44]; let first=&v[0]; v.push(72); | let mut v=vec![70,4,44]; let first=v[0]; v.push(72); | Copy instead of reference. | Rust |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
function test(index:string){{return index;}} test(11); | function test(index:string){{return index;}} test('world'); | Pass correct type. | TypeScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
41z = 10 | z41 = 10 | Variable cannot start with digit. | Python |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
var x int | var x int | Correct. | Go |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let num: number | null = null; num.toFixed(81); | let num: number | null = null; if(num!==null) num.toFixed(81); | Null check. | TypeScript |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
<ul><li>hello<li>test</ul> | <ul><li>hello</li><li>test</li></ul> | Close li. | HTML |
print('result') | print('result') | Correct. | R |
INSERT INTO products VALUES ('result',31) | INSERT INTO products (age, role) VALUES ('result',31); | Specify columns. | SQL |
const p:Person = {{name:'output'}}; | const p:Person = {{name:'output', age:60}}; | Add missing property. | TypeScript |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
for (foo in items) | for (foo of items) | for...in iterates keys. | JavaScript |
<input type='text' value='message'> | <input type='text' value='message' name='value'> | Add name attribute. | HTML |
fn bar() -> i32 {{ 43 }} | fn bar() -> i32 {{ 43 }} | Correct. | Rust |
.Order {{ color: #333; }} | .Order {{ color: #333; }} | Correct. | CSS |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
print('test') | print('test') | Correct. | R |
values[75] | if (values.indices.contains(75)) values[75] | Check index. | Kotlin |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
else
print('value') | else:
print('value') | Colon after else. | Python |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
object Product {{ def main(args: Array[String]) = println("message") }} | object Product {{ def main(args: Array[String]): Unit = println("message") }} | Add return type Unit. | Scala |
["value", 18] | ["value", 18] | Correct. | JSON |
{{'name':90, 'value' 32}} | {{'name':90, 'value':32}} | Colon missing. | Python |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
{{"id":"value" "id":1}} | {{"id":"value", "id":1}} | Add comma. | JSON |
val foo = 85; foo = 20 | var foo = 85; foo = 20 | Use var for reassignment. | Scala |
if [ $count = 48 ]; then | if [ "$count" = 48 ]; then | Quote variable. | Shell |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<hr></hr> | <hr> | Self-closing. | HTML |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
if (b = 84) {{}} | if (b === 84) {{}} | Use === for equality. | JavaScript |
var val int = 'test' | var val string = 'test' | Type mismatch. | Go |
data(95) | if length(data) >= 95, data(95), end | Check length. | MATLAB |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
[x*x for x in arr if x > 2] | [x*x for x in arr if x > 2] | Correct list comprehension. | Python |
local c = 99 | local c = 99 | Correct. | Lua |
echo 'info' | echo 'info'; | Add semicolon. | PHP |
let index = 88; index += 1; | let mut index = 88; index += 1; | Need mut to modify. | Rust |
bar | bar() | Add parentheses. | Kotlin |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let str1 = String::from("data"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
for c in range(54)
print(c) | for c in range(54):
print(c) | Colon after for. | Python |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
'result' + 81 | 'result' + str(81) | Can't add int to string. | Python |
if a = 12 | if a == 12 | Use ==. | Ruby |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
void main() {{ print('world') }} | void main() {{ print('world'); }} | Add semicolon. | Dart |
var x int | var x int | Correct. | Go |
jwt.sign({{id:96}}, 'password'); | jwt.sign({{id:96}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
{ "name": "output" } | { "name": "output" } | Correct. | JSON |
if temp = 34 then
print('value')
end | if temp == 34 then
print('value')
end | Use ==. | Lua |
$val = 80; if ($val = 80) {{}} | $val = 80; if ($val == 80) {{}} | Use ==. | PHP |
a == '33' | a === 33 | Use strict equality. | JavaScript |
val count: Int = 'output' | val count: String = 'output' | Fix type. | Kotlin |
def handle(count):
return count + 1 | def handle(count):
return count + 1 | Correct. | Python |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
[34, 8, 36 | [34, 8, 36] | Close bracket. | Ruby |
int index = 'output'; | String index = 'output'; | Type mismatch. | Dart |
function compute(item)
print(item)
end | function compute(item)
print(item)
end | Correct. | Lua |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
function baz() {{
return
{{key:'info'}}
}} | function baz() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
'data' + 56 | 'data' + 56.to_s | Convert int. | Ruby |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
x := 62 | x := 62 | Correct. | Go |
if result > 99
print('message') | if result > 99:
print('message') | Colon missing after if. | Python |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
print 'result' | print('result') | print needs parentheses. | Python |
val z = 'info' | val z = "info" | Double quotes. | Kotlin |
JOIN profiles ON products.id = profiles.id | JOIN profiles ON products.id = profiles.id | Correct. | SQL |
cin >> num; | int num;
cin >> num; | Declare variable. | C++ |
<user><name>message</name><name>44</name></user | <user><name>message</name><name>44</name></user> | Add closing >. | XML |
function process(bar:string){{return bar;}} process(65); | function process(bar:string){{return bar;}} process('value'); | Pass correct type. | TypeScript |
if (temp = 95) {} | if (temp == 95) {} | Use ==. | Dart |
class Order {{ int count; }}
obj.count=5; | class Order {{ public int count; }}
obj.count=5; | Make field public. | Java |
DELETE FROM orders WHERE status=22 | DELETE FROM orders WHERE status=22; | Add semicolon. | SQL |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
{{'name':'output'}} | {{"name":"output"}} | Use double quotes. | JSON |
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