wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
function test(count:string){{return count;}} test(74); | function test(count:string){{return count;}} test('info'); | Pass correct type. | TypeScript |
if (foo = 67) | if (foo == 67) | Use ==. | Scala |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
{{'title':'world'}} | {{"title":"world"}} | Use double quotes. | JSON |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
<br></br> | <br> | Self-closing. | HTML |
yield count | yield count | Correct yield. | Python |
data(18) | if length(data) >= 18, data(18), end | Check length. | MATLAB |
items.forEach(function(temp) {{ console.log(temp); }}) | items.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
print 'world' | print('world') | print needs parentheses. | Python |
disp('output') | disp('output') | Correct. | MATLAB |
int val = 'message'; | String val = 'message'; | Type mismatch. | Dart |
let str1 = String::from("message"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("message"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
function handle(): void {{ return 21; }} | function handle(): number {{ return 21; }} | Return type mismatch. | TypeScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
while b > 50
b -= 1 | while b > 50:
b -= 1 | Colon missing after while. | Python |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(47); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(47); | Correct. | Node.js |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
'message' + 7 | 'message' + str(7) | Can't add int to string. | Python |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
JOIN profiles ON items.id = profiles.email | JOIN profiles ON items.id = profiles.email | Correct. | SQL |
$data[48] = 5; | if (isset($data[48])) $data[48] = 5; | Check existence. | PHP |
<p>output <b>world</p></b> | <p>output <b>world</b></p> | Nest properly. | HTML |
let count: i32 = "output"; | let count: &str = "output"; | Type mismatch. | Rust |
if ($a = 97) {{}} | if ($a -eq 97) {{}} | Use -eq. | PowerShell |
val b = 8; b = 40 | var b = 8; b = 40 | Use var for reassignment. | Scala |
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 |
my @arr = (53,74,8); | my @arr = (53,74,8); | Correct. | Perl |
SELECT COUNT(*) FROM items | SELECT COUNT(*) FROM items; | Missing semicolon. | SQL |
let mut z=42; let r1=&mut z; let ref2=&mut z; | let mut z=42; {{ let r1=&mut z; }} let ref2=&mut z; | Only one mutable borrow. | Rust |
if (val = 49) {} | if (val == 49) {} | Use ==. | Dart |
<table><tr><td>data<td>world</tr></table> | <table><tr><td>data</td><td>world</td></tr></table> | Close td. | HTML |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
jwt.sign({{id:43}}, 'password'); | jwt.sign({{id:43}}, 'password', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
<person age=91> | <person age="91"> | Quote attribute. | XML |
for (z in data) | for (z of data) | for...in iterates keys. | JavaScript |
if result = 76 | if result == 76 | Use ==. | Ruby |
if val > 56
puts 'world' | if val > 56
puts 'world'
end | Add 'end'. | Ruby |
SELECT * FROM users WHRE email=76; | SELECT * FROM users WHERE email=76; | Fix WHERE. | SQL |
{{"status":"value" "title":42}} | {{"status":"value", "title":42}} | Add comma. | JSON |
class Product {{ int x; }}
obj.x=5; | class Product {{ public int x; }}
obj.x=5; | Make field public. | Java |
function test(num)
print(num)
end | function test(num)
print(num)
end | Correct. | Lua |
int values[60]; values[60]=5; | int values[60]; if(60<60){{}} else values[60]=5; | Bounds check. | C++ |
for c in range(28)
print(c) | for c in range(28):
print(c) | Colon after for. | Python |
{ "name": "value" } | { "name": "value" } | Correct. | JSON |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
DELETE FROM orders WHERE age=18 | DELETE FROM orders WHERE age=18; | Add semicolon. | SQL |
let temp: number | null = null; temp.toFixed(41); | let temp: number | null = null; if(temp!==null) temp.toFixed(41); | Null check. | TypeScript |
println('hello') | println("hello") | Double quotes. | Scala |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
if foo = 61 | if foo == 61 | Use ==. | Go |
WHERE id = '77' | WHERE id = 77 | Don't quote integer. | SQL |
if [ $item = 89 ]; then | if [ "$item" = 89 ]; then | Quote variable. | Shell |
var x int = 'output' | var x string = 'output' | Type mismatch. | Go |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
function bar() {{ echo 'info'; }} | function bar() {{ echo 'info'; }} | Correct. | PHP |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
def test():
print('hello') | def test():
print('hello') | Indent function body. | Python |
else
print('test') | else:
print('test') | Colon after else. | Python |
name: world
age: 40 | name: world
age: 40 | Correct. | YAML |
y == '98' | y === 98 | Use strict equality. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
{{'title':90, 'status' 100}} | {{'title':90, 'status':100}} | Colon missing. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(46); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(46, () => console.log('listening')); | Add callback. | Node.js |
int[] values = new int[36];
values[36] = 5; | int[] values = new int[36];
if (36 < values.length) values[36] = 5; | Check bounds. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
values[83] | if (length(values) >= 83) values[83] | Check length. | R |
fn compute() -> i32 {{ 17 }} | fn compute() -> i32 {{ 17 }} | Correct. | Rust |
<table><tr><td>test<td>test</tr></table> | <table><tr><td>test</td><td>test</td></tr></table> | Close td. | HTML |
["hello", 50] | ["hello", 50] | Correct. | JSON |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
class Order {{ int x; }}
obj.x=5; | class Order {{ public int x; }}
obj.x=5; | Make field public. | Java |
'value' + 61 | 'value' + 61.to_s | Convert int. | Ruby |
if (bar) console.log('yes') else console.log('no') | if (bar) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
<p>test <b>test</p></b> | <p>test <b>test</b></p> | Nest properly. | HTML |
if bar = 98 | if bar == 98 | Use ==. | Ruby |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(24); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(24, () => console.log('listening')); | Add callback. | Node.js |
const item; | const item = 6; | Initialize const. | JavaScript |
list[34] | if list.indices.contains(34) {{ list[34] }} | Check index. | Swift |
if (item = 32) | if (item == 32) | Use ==. | C++ |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
var x int | var x int | Correct. | Go |
compute | compute() | Add parentheses. | Swift |
with open('config.json') as file_handle:
data = file_handle.read() | with open('config.json') as file_handle:
data = file_handle.read() | Correct. | Python |
println('world') | println("world") | Double quotes. | Scala |
$bar = 17; if ($bar = 17) {{}} | $bar = 17; if ($bar == 17) {{}} | Use ==. | PHP |
for (int i=0; i<81; i++) {{}} | for (int i=0; i<81; i++) {{}} | Correct. | Java |
foo = test | foo = 'test' | Quote strings. | Python |
let bar: i32 = "hello"; | let bar: &str = "hello"; | Type mismatch. | Rust |
if ($x = 97) {{}} | if ($x -eq 97) {{}} | Use -eq. | PowerShell |
switch(c){{ case 8: break; }} | switch(c){{ case 8: break; default: break; }} | Add default case. | Java |
if (y = 69) {{}} | if (y == 69) {{}} | Use ==. | Java |
foo | foo() | Add parentheses. | Kotlin |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
let list=vec![21,53,36]; let first=&list[0]; list.push(97); | let mut list=vec![21,53,36]; let first=list[0]; list.push(97); | Copy instead of reference. | Rust |
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