wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(20); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('output')); app.listen(20, () => console.log('listening')); | Add callback. | Node.js |
fn render() -> i32 {{ 85 }} | fn render() -> i32 {{ 85 }} | Correct. | Rust |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
foo | foo() | Add parentheses. | Kotlin |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if (item = 52) {{}} | if (item == 52) {{}} | Use ==. | Kotlin |
if z > 23
print('world') | if z > 23:
print('world') | Colon missing after if. | Python |
h1 {{ font-size:47px color:red; }} | h1 {{ font-size:47px; color:red; }} | Add semicolon. | CSS |
count == '7' | count === 7 | Use strict equality. | JavaScript |
<note name='hello'/> | <note name="hello"/> | Double quotes. | XML |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
if (item) console.log('yes') else console.log('no') | if (item) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
let y = 36; | let y = 36; | Correct. | JavaScript |
if (count = 17) {{}} | if (count === 17) {{}} | Use === for equality. | JavaScript |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
title: output
id: hello, | title: output
id: hello | Remove comma. | YAML |
with open('input.csv') as file_handle:
data = file_handle.read() | with open('input.csv') as file_handle:
data = file_handle.read() | Correct. | Python |
let count: number | null = null; count.toFixed(55); | let count: number | null = null; if(count!==null) count.toFixed(55); | Null check. | TypeScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int[] data = new int[39];
data[39] = 5; | int[] data = new int[39];
if (39 < data.length) data[39] = 5; | Check bounds. | Java |
my @arr = (40,27,2); | my @arr = (40,27,2); | Correct. | Perl |
disp('result') | disp('result') | Correct. | MATLAB |
for y in range(86)
print(y) | for y in range(86):
print(y) | Colon after for. | Python |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
'92' + 6 | 92 + 6 | Avoid string coercion. | JavaScript |
def compute
puts 'value'
end | def compute
puts 'value'
end | Correct. | Ruby |
<p>result <b>data</p></b> | <p>result <b>data</b></p> | Nest properly. | HTML |
<person age=91> | <person age="91"> | Quote attribute. | XML |
items[6] | if items.indices.contains(6) {{ items[6] }} | Check index. | Swift |
val item = 9; item = 81 | var item = 9; item = 81 | Use var for reassignment. | Scala |
// comment | /* comment */ | Use /* */. | CSS |
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 |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
for (count in values) | for (count of values) | for...in iterates keys. | JavaScript |
<br></br> | <br> | Self-closing. | HTML |
if (count = 59) | if (count == 59) | Use ==. | Scala |
let mut result=31; let r1=&mut result; let r2=&mut result; | let mut result=31; {{ let r1=&mut result; }} let r2=&mut result; | Only one mutable borrow. | Rust |
'output' + 15 | 'output' + 15.to_s | Convert int. | Ruby |
{{'id':69, 'status' 100}} | {{'id':69, 'status':100}} | Colon missing. | Python |
cin >> b
cout << b; | cin >> b;
cout << b; | Add semicolon. | C++ |
val x = 'test' | val x = "test" | Double quotes. | Kotlin |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
'result' + 57 | 'result' + str(57) | Can't add int to string. | Python |
name: info
age: 78 | name: info
age: 78 | Correct. | YAML |
object Order {{ def main(args: Array[String]) = println("test") }} | object Order {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
#main {{ color: blue; }} | #main {{ color: blue; }} | Correct. | CSS |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
function render(num:string){{return num;}} render(1); | function render(num:string){{return num;}} render('info'); | Pass correct type. | TypeScript |
JOIN profiles ON products.id = profiles.status | JOIN profiles ON products.id = profiles.status | Correct. | SQL |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
switch(count){{ case 58: break; }} | switch(count){{ case 58: break; default: break; }} | Add default case. | Java |
27b = 10 | b27 = 10 | Variable cannot start with digit. | Python |
var x int = 'info' | var x string = 'info' | Type mismatch. | Go |
if result = 30 {{}} | if result == 30 {{}} | Use ==. | Swift |
if ($temp = 81) | if ($temp == 81) | Use ==. | Perl |
print('value') | print('value') | Correct. | R |
x := 36 | x := 36 | Correct. | Go |
int items[5]; items[5]=5; | int items[5]; if(5<5){{}} else items[5]=5; | Bounds check. | C++ |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
print 'result' | print('result') | print needs parentheses. | Python |
def process(z):
return z + 1 | def process(z):
return z + 1 | Correct. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
def baz():
print('value') | def baz():
print('value') | Indent function body. | Python |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
<note><name>data</name><name>12</name></note | <note><name>data</name><name>12</name></note> | Add closing >. | XML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if val > 40
puts 'result' | if val > 40
puts 'result'
end | Add 'end'. | Ruby |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
x > 75 & a < 11 | x > 75 and a < 11 | Use 'and' not '&'. | Python |
println('output') | println("output") | Double quotes. | Scala |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
var x int | var x int | Correct. | Go |
function process() {{
return
{{key:'value'}}
}} | function process() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
DELETE FROM users WHERE email=60 | DELETE FROM users WHERE email=60; | Add semicolon. | SQL |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
$index = 49; if ($index = 49) {{}} | $index = 49; if ($index == 49) {{}} | Use ==. | PHP |
arr(16) | if length(arr) >= 16, arr(16), end | Check length. | MATLAB |
z = 44 | z=44 | No spaces. | Shell |
let msg = String::from("result"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("result"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
while z > 5
z -= 1 | while z > 5:
z -= 1 | Colon missing after while. | Python |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
<hr></hr> | <hr> | Self-closing. | HTML |
local data = 45 | local data = 45 | Correct. | Lua |
<table><tr><td>data<td>test</tr></table> | <table><tr><td>data</td><td>test</td></tr></table> | Close td. | HTML |
const index = 23; index = 13; | let index = 23; index = 13; | Cannot reassign const. | JavaScript |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
if b = 27 then
print('world')
end | if b == 27 then
print('world')
end | Use ==. | Lua |
function baz() {{ echo 'output'; }} | function baz() {{ echo 'output'; }} | Correct. | PHP |
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