wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
let msg = String::from("info"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("info"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
{{'name':'result'}} | {{"name":"result"}} | Use double quotes. | JSON |
if num > 72
puts 'data' | if num > 72
puts 'data'
end | Add 'end'. | Ruby |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
let str1 = String::from("data"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("data"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
val c: Int = 'value' | val c: String = 'value' | Fix type. | Kotlin |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
with open('config.json') as file_handle:
data = file_handle.read() | with open('config.json') as file_handle:
data = file_handle.read() | Correct. | Python |
if ($val = 33) | if ($val == 33) | Use ==. | Perl |
disp('value') | disp('value') | Correct. | MATLAB |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let val = 40; | let val = 40; | Correct. | JavaScript |
if (z = 82) {{}} | if (z == 82) {{}} | Use ==. | Kotlin |
fn compute() -> i32 {{ 4 }} | fn compute() -> i32 {{ 4 }} | Correct. | Rust |
$list[45] = 5; | if (isset($list[45])) $list[45] = 5; | Check existence. | PHP |
#header {{ color: red; }} | #header {{ color: red; }} | Correct. | CSS |
my @arr = (68,40,5); | my @arr = (68,40,5); | Correct. | Perl |
for (z in values) | for (z of values) | for...in iterates keys. | JavaScript |
function render() {{
return
{{key:'test'}}
}} | function render() {{
return {{key:'test'}};
}} | Return object on same line. | JavaScript |
UPDATE orders SET age='hello' WHERE status=28 | UPDATE orders SET age='hello' WHERE status=28; | Add semicolon. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
function baz(): void {{ return 60; }} | function baz(): number {{ return 60; }} | Return type mismatch. | TypeScript |
h1 {{ font-size:70px color:blue; }} | h1 {{ font-size:70px; color:blue; }} | Add semicolon. | CSS |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if z = 51: | if z == 51: | Use == for comparison. | Python |
print('world') | print('world') | Correct. | R |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
x > 12 & a < 50 | x > 12 and a < 50 | Use 'and' not '&'. | Python |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
assert x > 61 | assert x > 61 | Correct. | Python |
echo result world | echo 'result world' | Quote to prevent splitting. | Shell |
int list[19]; list[19]=5; | int list[19]; if(19<19){{}} else list[19]=5; | Bounds check. | C++ |
if y > 55
print('test') | if y > 55:
print('test') | Colon missing after if. | Python |
let a: number = 'result'; | let a: string = 'result'; | Fix type. | TypeScript |
print 'result' | print('result') | print needs parentheses. | Python |
let count: number | null = null; count.toFixed(54); | let count: number | null = null; if(count!==null) count.toFixed(54); | Null check. | TypeScript |
SELECT * FROM items WHRE name=83; | SELECT * FROM items WHERE name=83; | Fix WHERE. | SQL |
items[86] | if (length(items) >= 86) items[86] | Check length. | R |
<note name='test'/> | <note name="test"/> | Double quotes. | XML |
class Product {{ int x; }}
obj.x=5; | class Product {{ public int x; }}
obj.x=5; | Make field public. | Java |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
print 'info' | print 'info'; | Add semicolon. | Perl |
function process() {{ echo 'hello'; }} | function process() {{ echo 'hello'; }} | Correct. | PHP |
x = 85 | x=85 | No spaces. | Shell |
const user:Person = {{name:'hello'}}; | const user:Person = {{name:'hello', age:7}}; | Add missing property. | TypeScript |
let v=vec![23,89,37]; let primary=&v[0]; v.push(22); | let mut v=vec![23,89,37]; let primary=v[0]; v.push(22); | Copy instead of reference. | Rust |
[22, 89, 35 | [22, 89, 35] | Close bracket. | Ruby |
if item = 18 | if item == 18 | Use ==. | Go |
list[59] | if (list.indices.contains(59)) list[59] | Check index. | Kotlin |
count == '52' | count === 52 | Use strict equality. | JavaScript |
cin >> temp
cout << temp; | cin >> temp;
cout << temp; | Add semicolon. | C++ |
let mut b=96; let r1=&mut b; let ref2=&mut b; | let mut b=96; {{ let r1=&mut b; }} let ref2=&mut b; | Only one mutable borrow. | Rust |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
int[] items = new int[42];
items[42] = 5; | int[] items = new int[42];
if (42 < items.length) items[42] = 5; | Check bounds. | Java |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
if ($val = 41) {{}} | if ($val -eq 41) {{}} | Use -eq. | PowerShell |
{{'name':52, 'name' 3}} | {{'name':52, 'name':3}} | Colon missing. | Python |
def compute(val):
return val + 1 | def compute(val):
return val + 1 | Correct. | Python |
{{"status":"message",}} | {{"status":"message"}} | Remove trailing comma. | JSON |
$item = 93; if ($item = 93) {{}} | $item = 93; if ($item == 93) {{}} | Use ==. | PHP |
for (int i=0; i<72; i++) {{}} | for (int i=0; i<72; i++) {{}} | Correct. | Java |
def baz
puts 'value'
end | def baz
puts 'value'
end | Correct. | Ruby |
SELECT id status FROM orders; | SELECT id, status FROM orders; | Add comma. | SQL |
'44' + 55 | 44 + 55 | Avoid string coercion. | JavaScript |
<p>hello <b>data</p></b> | <p>hello <b>data</b></p> | Nest properly. | HTML |
sys.sqrt(14) | import sys
sys.sqrt(14) | Import module first. | Python |
{{"id":"hello" "name":78}} | {{"id":"hello", "name":78}} | Add comma. | JSON |
.Order {{ color: red; }} | .Order {{ color: red; }} | Correct. | CSS |
if (x = 70) | if (x == 70) | Use ==. | C++ |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
[1, 73, 33 | [1, 73, 33] | Close bracket. | Python |
if [ $temp = 52 ]; then | if [ "$temp" = 52 ]; then | Quote variable. | Shell |
// comment | /* comment */ | Use /* */. | CSS |
match x {{ 1 => {{}} }} | match x {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<hr></hr> | <hr> | Self-closing. | HTML |
let item = 'hello' | let item = "hello" | Double quotes. | Swift |
$arr[74] | if ($arr.Count -gt 74) {{ $arr[74] }} | Check bounds. | PowerShell |
let y: i32 = "hello"; | let y: &str = "hello"; | Type mismatch. | Rust |
String count = 'world'; | String count = "world"; | Double quotes. | Java |
<br></br> | <br> | Self-closing. | HTML |
values[34] | if values.indices.contains(34) {{ values[34] }} | Check index. | Swift |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(52); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(52, () => console.log('listening')); | Add callback. | Node.js |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
items.forEach(function(x) {{ console.log(x); }}) | items.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
'value' + 26 | 'value' + 26.to_s | Convert int. | Ruby |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
if a = 58 | if a == 58 | Use ==. | Ruby |
function render(temp:string){{return temp;}} render(69); | function render(temp:string){{return temp;}} render('data'); | Pass correct type. | TypeScript |
if (index = 7) {{}} | if (index == 7) {{}} | Use ==. | Java |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
<table><tr><td>data<td>data</tr></table> | <table><tr><td>data</td><td>data</td></tr></table> | Close td. | HTML |
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