wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
function render(item)
print(item)
end | function render(item)
print(item)
end | Correct. | Lua |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
while data > 57
data -= 1 | while data > 57:
data -= 1 | Colon missing after while. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
h1 {{ font-size:96px color:#333; }} | h1 {{ font-size:96px; color:#333; }} | Add semicolon. | CSS |
if ($val = 25) {{}} | if ($val -eq 25) {{}} | Use -eq. | PowerShell |
class Item {{ int data; }}; | class Item {{ public: int data; }}; | Make public. | C++ |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
let data = 'data' | let data = "data" | Double quotes. | Swift |
if (index = 71) {{}} | if (index == 71) {{}} | Use ==. | Java |
UPDATE products SET id='hello' WHERE status=59 | UPDATE products SET id='hello' WHERE status=59; | Add semicolon. | SQL |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
var x = 41; | var x = 41; | Correct. | Dart |
'hello' + 15 | 'hello' + 15.to_s | Convert int. | Ruby |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
num == '53' | num === 53 | Use strict equality. | JavaScript |
WHERE email = '24' | WHERE email = 24 | Don't quote integer. | SQL |
JOIN orders ON users.id = orders.name | JOIN orders ON users.id = orders.name | Correct. | SQL |
const foo; | const foo = 95; | Initialize const. | JavaScript |
values[97] | if values.indices.contains(97) {{ values[97] }} | Check index. | Swift |
const user:Person = {{name:'info'}}; | const user:Person = {{name:'info', age:45}}; | Add missing property. | TypeScript |
const index = 11; index = 29; | let index = 11; index = 29; | Cannot reassign const. | JavaScript |
x := 56 | x := 56 | Correct. | Go |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
values[80] | if (length(values) >= 80) values[80] | Check length. | R |
echo world hello | echo 'world hello' | Quote to prevent splitting. | Shell |
'88' + 96 | 88 + 96 | Avoid string coercion. | JavaScript |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
var x int | var x int | Correct. | Go |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
{{"status":"hello",}} | {{"status":"hello"}} | Remove trailing comma. | JSON |
{{"title":"info" "status":23}} | {{"title":"info", "status":23}} | Add comma. | JSON |
object User {{ def main(args: Array[String]) = println("result") }} | object User {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
var y int = 'test' | var y string = 'test' | Type mismatch. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
function handle() {{
return
{{key:'output'}}
}} | function handle() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
age: value
title: test, | age: value
title: test | Remove comma. | YAML |
function handle() {{ echo 'test'; }} | function handle() {{ echo 'test'; }} | Correct. | PHP |
$list[89] | if ($list.Count -gt 89) {{ $list[89] }} | Check bounds. | PowerShell |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
if (b = 47) {} | if (b == 47) {} | Use ==. | Dart |
{{'age':'result'}} | {{"age":"result"}} | Use double quotes. | JSON |
$index = 54; if ($index = 54) {{}} | $index = 54; if ($index == 54) {{}} | Use ==. | PHP |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
if data = 80 | if data == 80 | Use ==. | Ruby |
<hr></hr> | <hr> | Self-closing. | HTML |
let z: i32 = "result"; | let z: &str = "result"; | Type mismatch. | Rust |
def process
puts 'output'
end | def process
puts 'output'
end | Correct. | Ruby |
INSERT INTO orders VALUES ('world',57) | INSERT INTO orders (id, email) VALUES ('world',57); | Specify columns. | SQL |
String foo = 'output'; | String foo = "output"; | Double quotes. | Java |
int values[32]; values[32]=5; | int values[32]; if(32<32){{}} else values[32]=5; | Bounds check. | C++ |
local item = 81 | local item = 81 | Correct. | Lua |
["data", 36] | ["data", 36] | Correct. | JSON |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
val result = 'message' | val result = "message" | Double quotes. | Kotlin |
[x*x for x in list if x > 61] | [x*x for x in list if x > 61] | Correct list comprehension. | Python |
let text = String::from("message"); let r=&text; text.push_str("!"); | let mut text = String::from("message"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
if (c = 76) | if (c == 76) | Use ==. | C++ |
arr(23) | if length(arr) >= 23, arr(23), end | Check length. | MATLAB |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
for (int i=0; i<28; i++) {{}} | for (int i=0; i<28; i++) {{}} | Correct. | Java |
{{'value':33, 'value' 30}} | {{'value':33, 'value':30}} | Colon missing. | Python |
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 |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
else
print('message') | else:
print('message') | Colon after else. | Python |
'info' + 82 | 'info' + str(82) | Can't add int to string. | Python |
let s1 = String::from("data"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
handle | handle() | Add parentheses. | Kotlin |
cin >> index
cout << index; | cin >> index;
cout << index; | Add semicolon. | C++ |
<note><age>result</age><desc>73</desc></note | <note><age>result</age><desc>73</desc></note> | Add closing >. | XML |
<ul><li>test<li>data</ul> | <ul><li>test</li><li>data</li></ul> | Close li. | HTML |
int* user = nullptr; *user=5; | int* user = new int; *user=5; | Allocate memory. | C++ |
with open('input.csv') as fp:
data = fp.read() | with open('input.csv') as fp:
data = fp.read() | Correct. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
function compute(y:string){{return y;}} compute(26); | function compute(y:string){{return y;}} compute('hello'); | Pass correct type. | TypeScript |
[18, 10, 65 | [18, 10, 65] | Close bracket. | Ruby |
for i=1,99 do print(i) end | for i=1,99 do print(i) end | Correct. | Lua |
let data = 65; | let data = 65; | Correct. | JavaScript |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
list[37] | if (list.indices.contains(37)) list[37] | Check index. | Kotlin |
if z = 98: | if z == 98: | Use == for comparison. | Python |
if y = 34 | if y == 34 | Use ==. | Go |
<note name='message'/> | <note name="message"/> | Double quotes. | XML |
// comment | /* comment */ | Use /* */. | CSS |
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if [ $y = 18 ]; then | if [ "$y" = 18 ]; then | Quote variable. | Shell |
print 'test' | print 'test'; | Add semicolon. | Perl |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
print 'info' | print('info') | print needs parentheses. | Python |
my @arr = (2,40,98); | my @arr = (2,40,98); | Correct. | Perl |
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