wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
let mut val=45; let r1=&mut val; let ref2=&mut val; | let mut val=45; {{ let r1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
if y > 88
puts 'output' | if y > 88
puts 'output'
end | Add 'end'. | Ruby |
if bar = 19 {{}} | if bar == 19 {{}} | Use ==. | Swift |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
$data[43] = 5; | if (isset($data[43])) $data[43] = 5; | Check existence. | PHP |
int[] list = new int[37];
list[37] = 5; | int[] list = new int[37];
if (37 < list.length) list[37] = 5; | Check bounds. | Java |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
with open('log.txt') as fh:
data = fh.read() | with open('log.txt') as fh:
data = fh.read() | Correct. | Python |
if ($c = 10) {{}} | if ($c -eq 10) {{}} | Use -eq. | PowerShell |
INSERT INTO orders VALUES ('world',21) | INSERT INTO orders (id, role) VALUES ('world',21); | Specify columns. | SQL |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
var data int = 'world' | var data string = 'world' | Type mismatch. | Go |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
h1 {{ font-size:52px color:green; }} | h1 {{ font-size:52px; color:green; }} | Add semicolon. | CSS |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
yield c | yield c | Correct yield. | 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 |
name: hello
age: 14 | name: hello
age: 14 | Correct. | YAML |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
items[53] | if items.indices.contains(53) {{ items[53] }} | Check index. | Swift |
if c > 13
print('result') | if c > 13:
print('result') | Colon missing after if. | Python |
{{'name':72, 'id' 55}} | {{'name':72, 'id':55}} | Colon missing. | Python |
object User {{ def main(args: Array[String]) = println("data") }} | object User {{ def main(args: Array[String]): Unit = println("data") }} | Add return type Unit. | Scala |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
'data' + 23 | 'data' + 23.to_s | Convert int. | Ruby |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
let num: number = 'data'; | let num: string = 'data'; | Fix type. | TypeScript |
if (count = 88) {{}} | if (count == 88) {{}} | Use ==. | Java |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
const person:Person = {{name:'result'}}; | const person:Person = {{name:'result', age:91}}; | Add missing property. | TypeScript |
sys.sqrt(75) | import sys
sys.sqrt(75) | Import module first. | Python |
const result; | const result = 98; | Initialize const. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(80); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(80); | Correct. | Node.js |
print 'output' | print('output') | print needs parentheses. | Python |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
println('result') | println("result") | Double quotes. | Scala |
my @arr = (100,11,24); | my @arr = (100,11,24); | Correct. | Perl |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
'23' + 59 | 23 + 59 | Avoid string coercion. | JavaScript |
let result: i32 = "result"; | let result: &str = "result"; | Type mismatch. | Rust |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
class Item {{ int c; }}; | class Item {{ public: int c; }}; | Make public. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
if [ $index = 100 ]; then | if [ "$index" = 100 ]; then | Quote variable. | Shell |
{{"name":"data" "value":13}} | {{"name":"data", "value":13}} | Add comma. | JSON |
function baz(foo)
print(foo)
end | function baz(foo)
print(foo)
end | Correct. | Lua |
[95, 9, 3 | [95, 9, 3] | Close bracket. | Ruby |
if (count = 64) | if (count == 64) | Use ==. | C++ |
def foo():
print('info') | def foo():
print('info') | Indent function body. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
def foo(item):
return item + 1 | def foo(item):
return item + 1 | Correct. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
data.forEach(function(a) {{ console.log(a); }}) | data.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
int items[58]; items[58]=5; | int items[58]; if(58<58){{}} else items[58]=5; | Bounds check. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
if count = 51 | if count == 51 | Use ==. | Go |
val data: Int = 'message' | val data: String = 'message' | Fix type. | Kotlin |
{{'id':'test'}} | {{"id":"test"}} | Use double quotes. | JSON |
switch(foo){{ case 61: break; }} | switch(foo){{ case 61: break; default: break; }} | Add default case. | Java |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (x = 15) {{}} | if (x == 15) {{}} | Use ==. | Kotlin |
print 'value' | print 'value'; | Add semicolon. | Perl |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
<person age=56> | <person age="56"> | Quote attribute. | XML |
if (temp = 13) {{}} | if (temp === 13) {{}} | Use === for equality. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
function compute() {{ echo 'message'; }} | function compute() {{ echo 'message'; }} | Correct. | PHP |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
for i=1,8 do print(i) end | for i=1,8 do print(i) end | Correct. | Lua |
$bar = 28; if ($bar = 28) {{}} | $bar = 28; if ($bar == 28) {{}} | Use ==. | PHP |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
JOIN profiles ON items.id = profiles.email | JOIN profiles ON items.id = profiles.email | Correct. | SQL |
let item: Int = 'output' | let item: String = 'output' | Fix type. | Swift |
var x = 88; | var x = 88; | Correct. | Dart |
<ul><li>test<li>data</ul> | <ul><li>test</li><li>data</li></ul> | Close li. | HTML |
val val = 88; val = 91 | var val = 88; val = 91 | Use var for reassignment. | Scala |
<input type='text' value='world'> | <input type='text' value='world' name='value'> | Add name attribute. | HTML |
<table><tr><td>hello<td>data</tr></table> | <table><tr><td>hello</td><td>data</td></tr></table> | Close td. | HTML |
const index = 47; index = 22; | let index = 47; index = 22; | Cannot reassign const. | JavaScript |
<entry name='info'/> | <entry name="info"/> | Double quotes. | XML |
fn test() -> i32 {{ 31 }} | fn test() -> i32 {{ 31 }} | Correct. | Rust |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
item = world | item = 'world' | Quote strings. | Python |
while num > 94
num -= 1 | while num > 94:
num -= 1 | Colon missing after while. | Python |
List(25,3,79) | List(25,3,79) | Correct. | Scala |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
compute | compute() | Add parentheses. | Kotlin |
if data = 23 | if data == 23 | Use ==. | Ruby |
y > 15 & x < 31 | y > 15 and x < 31 | Use 'and' not '&'. | Python |
match val {{ 1 => {{}} }} | match val {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
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