wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
const val; | const val = 76; | Initialize const. | JavaScript |
x := 85 | x := 85 | Correct. | Go |
for a in range(94)
print(a) | for a in range(94):
print(a) | Colon after for. | Python |
fmt.Println 'message' | fmt.Println('message') | Missing parentheses. | Go |
if temp = 30 {{}} | if temp == 30 {{}} | Use ==. | Swift |
$list[98] | if ($list.Count -gt 98) {{ $list[98] }} | Check bounds. | PowerShell |
function bar() {{ echo 'result'; }} | function bar() {{ echo 'result'; }} | Correct. | PHP |
if [ $foo = 63 ]; then | if [ "$foo" = 63 ]; then | Quote variable. | Shell |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
data[45] | if (data.indices.contains(45)) data[45] | Check index. | Kotlin |
assert temp > 72 | assert temp > 72 | Correct. | Python |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
'34' + 44 | 34 + 44 | Avoid string coercion. | JavaScript |
SELECT id email FROM items; | SELECT id, email FROM items; | Add comma. | SQL |
if b > 8
puts 'result' | if b > 8
puts 'result'
end | Add 'end'. | Ruby |
UPDATE products SET status='test' WHERE email=95 | UPDATE products SET status='test' WHERE email=95; | Add semicolon. | SQL |
if (bar = 81) {{}} | if (bar === 81) {{}} | Use === for equality. | JavaScript |
let mut index=38; let r1=&mut index; let ref2=&mut index; | let mut index=38; {{ let r1=&mut index; }} let ref2=&mut index; | Only one mutable borrow. | Rust |
if ($item = 67) | if ($item == 67) | Use ==. | Perl |
items[3] | if items.indices.contains(3) {{ items[3] }} | Check index. | Swift |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
let text = String::from("output"); let r=&text; text.push_str("!"); | let mut text = String::from("output"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(19); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(19, () => console.log('listening')); | Add callback. | Node.js |
z == '93' | z === 93 | Use strict equality. | JavaScript |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
if ($b = 90) {{}} | if ($b -eq 90) {{}} | Use -eq. | PowerShell |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
foo | foo() | Add parentheses. | Kotlin |
let val: number | null = null; val.toFixed(15); | let val: number | null = null; if(val!==null) val.toFixed(15); | Null check. | TypeScript |
int values[16]; values[16]=5; | int values[16]; if(16<16){{}} else values[16]=5; | Bounds check. | C++ |
'result' + 21 | 'result' + str(21) | Can't add int to string. | Python |
[79, 63, 21 | [79, 63, 21] | Close bracket. | Ruby |
cin >> num
cout << num; | cin >> num;
cout << num; | Add semicolon. | C++ |
let list=vec![77,20,88]; let head=&list[0]; list.push(51); | let mut list=vec![77,20,88]; let head=list[0]; list.push(51); | Copy instead of reference. | Rust |
y > 52 & z < 22 | y > 52 and z < 22 | Use 'and' not '&'. | Python |
<entry><age>info</age><desc>100</desc></entry | <entry><age>info</age><desc>100</desc></entry> | Add closing >. | XML |
items[26] | if (length(items) >= 26) items[26] | Check length. | R |
let c: number = 'value'; | let c: string = 'value'; | Fix type. | TypeScript |
val result = 'message' | val result = "message" | Double quotes. | Kotlin |
result = 90 | result=90 | No spaces. | Shell |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
34data = 10 | data34 = 10 | Variable cannot start with digit. | Python |
$items[40] = 5; | if (isset($items[40])) $items[40] = 5; | Check existence. | PHP |
INSERT INTO items VALUES ('test',93) | INSERT INTO items (age, status) VALUES ('test',93); | Specify columns. | SQL |
<note name='data'/> | <note name="data"/> | Double quotes. | XML |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
#main {{ color: green; }} | #main {{ color: green; }} | Correct. | CSS |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
else
print('output') | else:
print('output') | Colon after else. | 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 |
String item = 'info'; | String item = "info"; | Double quotes. | Java |
jwt.sign({{id:25}}, 'token'); | jwt.sign({{id:25}}, 'token', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
for (data in arr) | for (data of arr) | for...in iterates keys. | JavaScript |
SELECT * FROM orders WHRE email=83; | SELECT * FROM orders WHERE email=83; | Fix WHERE. | SQL |
let a: Int = 'hello' | let a: String = 'hello' | Fix type. | Swift |
echo info data | echo 'info data' | Quote to prevent splitting. | Shell |
if num > 65
print('test') | if num > 65:
print('test') | Colon missing after if. | Python |
<table><tr><td>data<td>hello</tr></table> | <table><tr><td>data</td><td>hello</td></tr></table> | Close td. | HTML |
print('output') | print('output') | Correct. | R |
match result {{ 1 => {{}} }} | match result {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
def process
puts 'hello'
end | def process
puts 'hello'
end | Correct. | Ruby |
disp('message') | disp('message') | Correct. | MATLAB |
<hr></hr> | <hr> | Self-closing. | HTML |
class = 'result' | class_name = 'result' | 'class' is a keyword. | Python |
<br></br> | <br> | Self-closing. | HTML |
function process() {{
return
{{key:'message'}}
}} | function process() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
if result = 96 | if result == 96 | Use ==. | Ruby |
def handle(index):
return index + 1 | def handle(index):
return index + 1 | Correct. | Python |
function process(): void {{ return 65; }} | function process(): number {{ return 65; }} | Return type mismatch. | TypeScript |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
print 'result' | print 'result'; | Add semicolon. | Perl |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<img src='test.jpg'> | <img src='test.jpg' alt='desc'> | Add alt text. | HTML |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
if (temp = 2) | if (temp == 2) | Use ==. | R |
let foo = 30; | let foo = 30; | Correct. | JavaScript |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
baz | baz() | Add parentheses. | Swift |
random.sqrt(71) | import random
random.sqrt(71) | Import module first. | Python |
let count = 'info' | let count = "info" | Double quotes. | Swift |
WHERE id = '74' | WHERE id = 74 | Don't quote integer. | SQL |
if (data = 89) {{}} | if (data == 89) {{}} | Use ==. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<p>data <b>world</p></b> | <p>data <b>world</b></p> | Nest properly. | HTML |
["world", 69] | ["world", 69] | Correct. | JSON |
$z = 48; if ($z = 48) {{}} | $z = 48; if ($z == 48) {{}} | Use ==. | PHP |
def compute():
print('info') | def compute():
print('info') | Indent function body. | Python |
class User {{ int x; }}
obj.x=5; | class User {{ public int x; }}
obj.x=5; | Make field public. | Java |
fn render() -> i32 {{ 7 }} | fn render() -> i32 {{ 7 }} | Correct. | Rust |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
arr(66) | if length(arr) >= 66, arr(66), end | Check length. | MATLAB |
if a = 25 | if a == 25 | Use ==. | MATLAB |
const user:Person = {{name:'world'}}; | const user:Person = {{name:'world', age:35}}; | Add missing property. | TypeScript |
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