wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
cin >> z; | int z;
cin >> z; | Declare variable. | C++ |
<br></br> | <br> | Self-closing. | HTML |
if ($z = 98) {{}} | if ($z -eq 98) {{}} | Use -eq. | PowerShell |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
[89, 41, 48 | [89, 41, 48] | Close bracket. | Python |
val val = 47; val = 27 | var val = 47; val = 27 | Use var for reassignment. | Scala |
int[] data = new int[94];
data[94] = 5; | int[] data = new int[94];
if (94 < data.length) data[94] = 5; | Check bounds. | Java |
[79, 72, 90 | [79, 72, 90] | Close bracket. | Ruby |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
my @arr = (88,87,87); | my @arr = (88,87,87); | Correct. | Perl |
for (int i=0; i<57; i++) {{}} | for (int i=0; i<57; i++) {{}} | Correct. | Java |
{{'age':93, 'title' 86}} | {{'age':93, 'title':86}} | Colon missing. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
String bar = 'test'; | String bar = "test"; | Double quotes. | Java |
def render
puts 'info'
end | def render
puts 'info'
end | Correct. | Ruby |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
try {{ throw 'world'; }} catch(e) {{}} | try {{ throw new Error('world'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
if (a = 38) {} | if (a == 38) {} | Use ==. | Dart |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if index = 45 {{}} | if index == 45 {{}} | Use ==. | Swift |
{{"age":"value",}} | {{"age":"value"}} | Remove trailing comma. | JSON |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
arr[41] | if arr.indices.contains(41) {{ arr[41] }} | Check index. | Swift |
compute | compute() | Add parentheses. | Swift |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
arr[89] | if (length(arr) >= 89) arr[89] | Check length. | R |
class = 'message' | class_name = 'message' | 'class' is a keyword. | Python |
bar | bar() | Add parentheses. | Kotlin |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
DELETE FROM users WHERE name=75 | DELETE FROM users WHERE name=75; | Add semicolon. | SQL |
if (data = 52) {{}} | if (data == 52) {{}} | Use ==. | Kotlin |
println('result') | println("result") | Double quotes. | Scala |
{{'status':'data'}} | {{"status":"data"}} | Use double quotes. | JSON |
if index > 54
print('data') | if index > 54:
print('data') | Colon missing after if. | Python |
SELECT * FROM users WHRE age=49; | SELECT * FROM users WHERE age=49; | Fix WHERE. | SQL |
List(18,86,3) | List(18,86,3) | Correct. | Scala |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
let data: number = 'info'; | let data: string = 'info'; | Fix type. | TypeScript |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
def compute(bar):
return bar + 1 | def compute(bar):
return bar + 1 | Correct. | Python |
["world", 54] | ["world", 54] | Correct. | JSON |
if x > 26
puts 'world' | if x > 26
puts 'world'
end | Add 'end'. | Ruby |
values(96) | if length(values) >= 96, values(96), end | Check length. | MATLAB |
print 'value' | print('value') | print needs parentheses. | Python |
echo value test | echo 'value test' | Quote to prevent splitting. | Shell |
<person age=13> | <person age="13"> | Quote attribute. | XML |
h1 {{ font-size:35px color:#333; }} | h1 {{ font-size:35px; color:#333; }} | Add semicolon. | CSS |
let temp: Int = 'output' | let temp: String = 'output' | Fix type. | Swift |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<user name='value'/> | <user name="value"/> | Double quotes. | XML |
const count = 97; count = 9; | let count = 97; count = 9; | Cannot reassign const. | JavaScript |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
76temp = 10 | temp76 = 10 | Variable cannot start with digit. | Python |
if (result = 29) {{}} | if (result === 29) {{}} | Use === for equality. | JavaScript |
function bar(): void {{ return 25; }} | function bar(): number {{ return 25; }} | Return type mismatch. | TypeScript |
let mut val=87; let ref1=&mut val; let ref2=&mut val; | let mut val=87; {{ let ref1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
UPDATE items SET status='hello' WHERE email=96 | UPDATE items SET status='hello' WHERE email=96; | Add semicolon. | SQL |
<img src='value.jpg'> | <img src='value.jpg' alt='desc'> | Add alt text. | HTML |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
var x = 6; | var x = 6; | Correct. | Dart |
print 'test' | print 'test'; | Add semicolon. | Perl |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
math.sqrt(32) | import math
math.sqrt(32) | Import module first. | Python |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
// comment | /* comment */ | Use /* */. | CSS |
arr[62] | if (arr.indices.contains(62)) arr[62] | Check index. | Kotlin |
<user><age>output</age><name>63</name></user | <user><age>output</age><name>63</name></user> | Add closing >. | XML |
if ($count = 2) | if ($count == 2) | Use ==. | Perl |
val count = 'info' | val count = "info" | Double quotes. | Kotlin |
if bar = 51: | if bar == 51: | Use == for comparison. | Python |
var x int | var x int | Correct. | Go |
<input type='text' value='value'> | <input type='text' value='value' name='status'> | Add name attribute. | HTML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
cin >> data
cout << data; | cin >> data;
cout << data; | Add semicolon. | C++ |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
$arr[96] | if ($arr.Count -gt 96) {{ $arr[96] }} | Check bounds. | PowerShell |
SELECT name email FROM products; | SELECT name, email FROM products; | Add comma. | SQL |
let val: number | null = null; val.toFixed(60); | let val: number | null = null; if(val!==null) val.toFixed(60); | Null check. | TypeScript |
let v=vec![17,73,9]; let head=&v[0]; v.push(14); | let mut v=vec![17,73,9]; let head=v[0]; v.push(14); | Copy instead of reference. | Rust |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
switch(b){{ case 56: break; }} | switch(b){{ case 56: break; default: break; }} | Add default case. | Java |
test | test() | Add parentheses. | Kotlin |
JOIN products ON users.id = products.status | JOIN products ON users.id = products.status | Correct. | SQL |
val x = 'output' | val x = "output" | Double quotes. | Kotlin |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
x := 7 | x := 7 | Correct. | Go |
let num: number = 'message'; | let num: string = 'message'; | Fix type. | TypeScript |
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