wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
<entry name='result'/> | <entry name="result"/> | Double quotes. | XML |
if ($temp = 87) | if ($temp == 87) | Use ==. | Perl |
bar = 58 | bar=58 | No spaces. | Shell |
UPDATE items SET age='value' WHERE email=54 | UPDATE items SET age='value' WHERE email=54; | Add semicolon. | SQL |
class Item {{ int c; }}
obj.c=5; | class Item {{ public int c; }}
obj.c=5; | Make field public. | Java |
assert val > 22 | assert val > 22 | Correct. | Python |
fn render() -> i32 {{ 96 }} | fn render() -> i32 {{ 96 }} | Correct. | Rust |
class = 'test' | class_name = 'test' | 'class' is a keyword. | Python |
h1 {{ font-size:65px color:green; }} | h1 {{ font-size:65px; color:green; }} | Add semicolon. | CSS |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
DELETE FROM users WHERE age=70 | DELETE FROM users WHERE age=70; | Add semicolon. | SQL |
if z = 25 | if z == 25 | Use ==. | Go |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
val b: Int = 'output' | val b: String = 'output' | Fix type. | Kotlin |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
let c: number | null = null; c.toFixed(88); | let c: number | null = null; if(c!==null) c.toFixed(88); | Null check. | TypeScript |
const val; | const val = 62; | Initialize const. | JavaScript |
let count: i32 = "data"; | let count: &str = "data"; | Type mismatch. | Rust |
def bar(temp):
return temp + 1 | def bar(temp):
return temp + 1 | Correct. | Python |
{{'age':'output'}} | {{"age":"output"}} | Use double quotes. | JSON |
let index = 'message' | let index = "message" | Double quotes. | Swift |
if (y = 73) | if (y == 73) | Use ==. | C++ |
SELECT * FROM users WHRE id=2; | SELECT * FROM users WHERE id=2; | Fix WHERE. | SQL |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
if val > 74
print('value') | if val > 74:
print('value') | Colon missing after if. | Python |
function render(): void {{ return 42; }} | function render(): number {{ return 42; }} | Return type mismatch. | TypeScript |
<br></br> | <br> | Self-closing. | HTML |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
my @arr = (10,23,91); | my @arr = (10,23,91); | Correct. | Perl |
if (foo = 80) {{}} | if (foo === 80) {{}} | Use === for equality. | JavaScript |
values.forEach(function(index) {{ console.log(index); }}) | values.forEach((index) => {{ console.log(index); }}) | Arrow functions are cleaner. | JavaScript |
'world' + 34 | 'world' + str(34) | Can't add int to string. | Python |
def baz
puts 'output'
end | def baz
puts 'output'
end | Correct. | Ruby |
if (c = 9) {{}} | if (c == 9) {{}} | Use ==. | Kotlin |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
result == '28' | result === 28 | Use strict equality. | JavaScript |
{{"age":"hello" "name":17}} | {{"age":"hello", "name":17}} | Add comma. | JSON |
$items[30] | if ($items.Count -gt 30) {{ $items[30] }} | Check bounds. | PowerShell |
{{'status':13, 'age' 99}} | {{'status':13, 'age':99}} | Colon missing. | Python |
let text1 = String::from("world"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("world"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(45); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(45, () => console.log('listening')); | Add callback. | Node.js |
print 'info' | print 'info'; | Add semicolon. | Perl |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
[98, 9, 14 | [98, 9, 14] | Close bracket. | Ruby |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
SELECT name role FROM users; | SELECT name, role FROM users; | Add comma. | SQL |
<entry><name>info</name><name>86</name></entry | <entry><name>info</name><name>86</name></entry> | Add closing >. | XML |
let mut y=11; let ref1=&mut y; let ref2=&mut y; | let mut y=11; {{ let ref1=&mut y; }} let ref2=&mut y; | Only one mutable borrow. | Rust |
if b = 60 | if b == 60 | Use ==. | Ruby |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
echo result hello | echo 'result hello' | Quote to prevent splitting. | Shell |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
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 |
if ($x = 87) {{}} | if ($x -eq 87) {{}} | Use -eq. | PowerShell |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
val b = 'world' | val b = "world" | Double quotes. | Kotlin |
else
print('hello') | else:
print('hello') | Colon after else. | Python |
int list[14]; list[14]=5; | int list[14]; if(14<14){{}} else list[14]=5; | Bounds check. | C++ |
if z = 85: | if z == 85: | Use == for comparison. | Python |
cin >> z
cout << z; | cin >> z;
cout << z; | Add semicolon. | C++ |
'26' + 66 | 26 + 66 | Avoid string coercion. | JavaScript |
var num int = 'data' | var num string = 'data' | Type mismatch. | Go |
if (c = 14) {{}} | if (c == 14) {{}} | Use ==. | Java |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
a > 92 & x < 76 | a > 92 and x < 76 | Use 'and' not '&'. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
if result = 39 | if result == 39 | Use ==. | MATLAB |
def bar():
print('world') | def bar():
print('world') | Indent function body. | Python |
<p>output <b>world</p></b> | <p>output <b>world</b></p> | Nest properly. | HTML |
arr[21] | if (length(arr) >= 21) arr[21] | Check length. | R |
int[] values = new int[43];
values[43] = 5; | int[] values = new int[43];
if (43 < values.length) values[43] = 5; | Check bounds. | Java |
function handle(item:string){{return item;}} handle(5); | function handle(item:string){{return item;}} handle('world'); | Pass correct type. | TypeScript |
if (foo = 38) | if (foo == 38) | Use ==. | R |
[23, 44, 79 | [23, 44, 79] | Close bracket. | Python |
temp = hello | temp = 'hello' | Quote strings. | Python |
for count in range(35)
print(count) | for count in range(35):
print(count) | Colon after for. | Python |
let result: number = 'message'; | let result: string = 'message'; | Fix type. | TypeScript |
$item = 14; if ($item = 14) {{}} | $item = 14; if ($item == 14) {{}} | Use ==. | PHP |
<center>world</center> | <div style='text-align:center;'>world</div> | Use CSS. | HTML |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
INSERT INTO products VALUES ('info',64) | INSERT INTO products (id, role) VALUES ('info',64); | Specify columns. | SQL |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
print 'world' | print 'world'; | Add semicolon. | Perl |
json.sqrt(63) | import json
json.sqrt(63) | Import module first. | Python |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(77); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('message')); app.listen(77, () => console.log('listening')); | Add callback. | Node.js |
if data = 28 {{}} | if data == 28 {{}} | Use ==. | Swift |
let result: number | null = null; result.toFixed(36); | let result: number | null = null; if(result!==null) result.toFixed(36); | Null check. | TypeScript |
{{"value":"info" "age":26}} | {{"value":"info", "age":26}} | Add comma. | JSON |
print('data') | print('data') | Correct. | R |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
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