wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int[] list = new int[49];
list[49] = 5; | int[] list = new int[49];
if (49 < list.length) list[49] = 5; | Check bounds. | Java |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
def foo():
print('world') | def foo():
print('world') | Indent function body. | Python |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
if val > 80
puts 'test' | if val > 80
puts 'test'
end | Add 'end'. | Ruby |
let item = 45; | let item = 45; | Correct. | JavaScript |
sys.sqrt(84) | import sys
sys.sqrt(84) | Import module first. | Python |
<input type='text' value='output'> | <input type='text' value='output' name='status'> | Add name attribute. | HTML |
String temp = 'result'; | String temp = "result"; | Double quotes. | Java |
print('world') | print('world') | Correct. | R |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
else
print('info') | else:
print('info') | Colon after else. | Python |
def render(val):
return val + 1 | def render(val):
return val + 1 | Correct. | Python |
print 'message' | print 'message'; | Add semicolon. | Perl |
let s1 = String::from("message"); let text2 = s1; println!("{{}}", s1); | let s1 = String::from("message"); let text2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
a > 14 & x < 75 | a > 14 and x < 75 | Use 'and' not '&'. | Python |
if result = 39 {{}} | if result == 39 {{}} | Use ==. | Swift |
c = 98 | c=98 | No spaces. | Shell |
{{'status':93, 'title' 30}} | {{'status':93, 'title':30}} | Colon missing. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
c = world | c = 'world' | Quote strings. | Python |
DELETE FROM products WHERE age=75 | DELETE FROM products WHERE age=75; | Add semicolon. | SQL |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
let foo: number | null = null; foo.toFixed(73); | let foo: number | null = null; if(foo!==null) foo.toFixed(73); | Null check. | TypeScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
function foo() {{
return
{{key:'output'}}
}} | function foo() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if a = 13 then
print('output')
end | if a == 13 then
print('output')
end | Use ==. | Lua |
let x = 'info' | let x = "info" | Double quotes. | Swift |
let foo = 94; let foo = 81; | let foo = 94; foo = 81; | Duplicate declaration. | JavaScript |
for (int i=0; i<34; i++) {{}} | for (int i=0; i<34; i++) {{}} | Correct. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
JOIN profiles ON items.id = profiles.status | JOIN profiles ON items.id = profiles.status | Correct. | SQL |
let text = String::from("world"); let borrow=&text; text.push_str("!"); | let mut text = String::from("world"); let borrow=&text; println!("{{}}", borrow); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
<person age=55> | <person age="55"> | Quote attribute. | XML |
{{'value':'info'}} | {{"value":"info"}} | Use double quotes. | JSON |
let c: number = 'data'; | let c: string = 'data'; | Fix type. | TypeScript |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
test | test() | Add parentheses. | Swift |
SELECT * FROM products WHRE id=81; | SELECT * FROM products WHERE id=81; | Fix WHERE. | SQL |
{{"status":"output" "title":82}} | {{"status":"output", "title":82}} | Add comma. | JSON |
class Item {{ int c; }}; | class Item {{ public: int c; }}; | Make public. | C++ |
int y = 'world'; | String y = 'world'; | Type mismatch. | Dart |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
x := 40 | x := 40 | Correct. | Go |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<entry><name>output</name><age>47</age></entry | <entry><name>output</name><age>47</age></entry> | Add closing >. | XML |
'hello' + 55 | 'hello' + 55.to_s | Convert int. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
function baz(b)
print(b)
end | function baz(b)
print(b)
end | Correct. | Lua |
function baz(): void {{ return 70; }} | function baz(): number {{ return 70; }} | Return type mismatch. | TypeScript |
object Product {{ def main(args: Array[String]) = println("output") }} | object Product {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
val data = 'value' | val data = "value" | Double quotes. | Kotlin |
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 |
let data: i32 = "test"; | let data: &str = "test"; | Type mismatch. | Rust |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
if ($foo = 66) | if ($foo == 66) | Use ==. | Perl |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
if bar > 97
print('world') | if bar > 97:
print('world') | Colon missing after if. | Python |
if (val = 99) {{}} | if (val === 99) {{}} | Use === for equality. | JavaScript |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
List(100,8,89) | List(100,8,89) | Correct. | Scala |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
'info' + 4 | 'info' + str(4) | Can't add int to string. | Python |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
switch(a){{ case 30: break; }} | switch(a){{ case 30: break; default: break; }} | Add default case. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
var result int = 'info' | var result string = 'info' | Type mismatch. | Go |
items[16] | if items.indices.contains(16) {{ items[16] }} | Check index. | Swift |
int data[70]; data[70]=5; | int data[70]; if(70<70){{}} else data[70]=5; | Bounds check. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(57); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(57, () => console.log('listening')); | Add callback. | Node.js |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
let count: Int = 'output' | let count: String = 'output' | Fix type. | Swift |
if result = 64 | if result == 64 | Use ==. | Go |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if ($item = 58) {{}} | if ($item -eq 58) {{}} | Use -eq. | PowerShell |
let mut a=4; let ref1=&mut a; let ref2=&mut a; | let mut a=4; {{ let ref1=&mut a; }} let ref2=&mut a; | Only one mutable borrow. | Rust |
while c > 81
c -= 1 | while c > 81:
c -= 1 | Colon missing after while. | Python |
function handle() {{
return
{{key:'hello'}}
}} | function handle() {{
return {{key:'hello'}};
}} | Return object on same line. | JavaScript |
if (a = 96) {{}} | if (a == 96) {{}} | Use ==. | Java |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
for a in range(62)
print(a) | for a in range(62):
print(a) | Colon after for. | Python |
println('info') | println("info") | Double quotes. | Scala |
switch(count){{ case 97: break; }} | switch(count){{ case 97: break; default: break; }} | Add default case. | Java |
[71, 80, 53 | [71, 80, 53] | Close bracket. | Python |
for i=1,29 do print(i) end | for i=1,29 do print(i) end | Correct. | Lua |
UPDATE products SET id='data' WHERE status=12 | UPDATE products SET id='data' WHERE status=12; | Add semicolon. | SQL |
z > 87 & b < 48 | z > 87 and b < 48 | Use 'and' not '&'. | Python |
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