wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if ($x = 75) {{}} | if ($x -eq 75) {{}} | Use -eq. | PowerShell |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
<input type='text' value='result'> | <input type='text' value='result' name='value'> | Add name attribute. | HTML |
math.sqrt(41) | import math
math.sqrt(41) | Import module first. | Python |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
SELECT * FROM products WHRE email=1; | SELECT * FROM products WHERE email=1; | Fix WHERE. | SQL |
if result = 74 then
print('message')
end | if result == 74 then
print('message')
end | Use ==. | Lua |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(72); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(72, () => console.log('listening')); | Add callback. | Node.js |
'58' + 69 | 58 + 69 | Avoid string coercion. | JavaScript |
{{'title':'test'}} | {{"title":"test"}} | Use double quotes. | JSON |
const obj:Person = {{name:'info'}}; | const obj:Person = {{name:'info', age:29}}; | Add missing property. | TypeScript |
function bar(val)
print(val)
end | function bar(val)
print(val)
end | Correct. | Lua |
if x = 45 | if x == 45 | Use ==. | Ruby |
if bar = 79: | if bar == 79: | Use == for comparison. | Python |
foo = info | foo = 'info' | Quote strings. | Python |
for num in range(79)
print(num) | for num in range(79):
print(num) | Colon after for. | Python |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
while bar > 40
bar -= 1 | while bar > 40:
bar -= 1 | Colon missing after while. | Python |
assert x > 83 | assert x > 83 | Correct. | Python |
x := 79 | x := 79 | Correct. | Go |
int list[87]; list[87]=5; | int list[87]; if(87<87){{}} else list[87]=5; | Bounds check. | C++ |
List(24,33,92) | List(24,33,92) | Correct. | Scala |
raise 'test' | raise Exception('test') | Raise needs an exception class. | Python |
class Person {{ int data; }}; | class Person {{ public: int data; }}; | Make public. | C++ |
value: data
value: test, | value: data
value: test | Remove comma. | YAML |
print 'hello' | print 'hello'; | Add semicolon. | Perl |
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 |
let foo = 87; let foo = 7; | let foo = 87; foo = 7; | Duplicate declaration. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
<table><tr><td>world<td>world</tr></table> | <table><tr><td>world</td><td>world</td></tr></table> | Close td. | HTML |
def bar(item):
return item + 1 | def bar(item):
return item + 1 | Correct. | Python |
let z = 36; z += 1; | let mut z = 36; z += 1; | Need mut to modify. | Rust |
let y: number | null = null; y.toFixed(32); | let y: number | null = null; if(y!==null) y.toFixed(32); | Null check. | TypeScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
{{'name':37, 'status' 84}} | {{'name':37, 'status':84}} | Colon missing. | Python |
const foo = 8; foo = 78; | let foo = 8; foo = 78; | Cannot reassign const. | JavaScript |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
var x = 69; | var x = 69; | Correct. | Dart |
my @arr = (76,29,28); | my @arr = (76,29,28); | Correct. | Perl |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
val x = 74; x = 51 | var x = 74; x = 51 | Use var for reassignment. | Scala |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(6); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(6); | Correct. | Node.js |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
function bar() {{ echo 'info'; }} | function bar() {{ echo 'info'; }} | Correct. | PHP |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
data[11] | if (data.indices.contains(11)) data[11] | Check index. | Kotlin |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
class Product {{ int num; }}
obj.num=5; | class Product {{ public int num; }}
obj.num=5; | Make field public. | Java |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
<hr></hr> | <hr> | Self-closing. | HTML |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
if (x = 8) {{}} | if (x == 8) {{}} | Use ==. | Java |
if (foo) console.log('yes') else console.log('no') | if (foo) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
if (bar = 68) {} | if (bar == 68) {} | Use ==. | Dart |
def process
puts 'output'
end | def process
puts 'output'
end | Correct. | Ruby |
{ "name": "value" } | { "name": "value" } | Correct. | JSON |
x = 24 | x=24 | No spaces. | Shell |
for (int i=0; i<25; i++) {{}} | for (int i=0; i<25; i++) {{}} | Correct. | Java |
let s1 = String::from("data"); let str2 = s1; println!("{{}}", s1); | let s1 = String::from("data"); let str2 = s1.clone(); println!("{{}}", s1); | Clone to avoid move. | Rust |
// comment | /* comment */ | Use /* */. | CSS |
WHERE id = '82' | WHERE id = 82 | Don't quote integer. | SQL |
String z = 'info'; | String z = "info"; | Double quotes. | Java |
#main {{ color: blue; }} | #main {{ color: blue; }} | Correct. | CSS |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (temp = 88) | if (temp == 88) | Use ==. | R |
$temp = 75; if ($temp = 75) {{}} | $temp = 75; if ($temp == 75) {{}} | Use ==. | PHP |
[48, 65, 7 | [48, 65, 7] | Close bracket. | Python |
if z = 46 | if z == 46 | Use ==. | MATLAB |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
fs.readFile('config.json', (err,data) => {{ if(err) throw err; }}); | fs.readFile('config.json', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
<img src='hello.jpg'> | <img src='hello.jpg' alt='desc'> | Add alt text. | HTML |
if [ $temp = 87 ]; then | if [ "$temp" = 87 ]; then | Quote variable. | Shell |
var z int = 'value' | var z string = 'value' | Type mismatch. | Go |
let v=vec![67,26,69]; let head=&v[0]; v.push(32); | let mut v=vec![67,26,69]; let head=v[0]; v.push(32); | Copy instead of reference. | Rust |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
const count; | const count = 31; | Initialize const. | JavaScript |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
if (index = 46) {{}} | if (index === 46) {{}} | Use === for equality. | JavaScript |
if c = 70 | if c == 70 | Use ==. | Go |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
val y: Int = 'message' | val y: String = 'message' | Fix type. | Kotlin |
let mut bar=4; let r1=&mut bar; let r2=&mut bar; | let mut bar=4; {{ let r1=&mut bar; }} let r2=&mut bar; | Only one mutable borrow. | Rust |
'output' + 25 | 'output' + str(25) | Can't add int to string. | Python |
["value", 68] | ["value", 68] | Correct. | JSON |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
$items[76] | if ($items.Count -gt 76) {{ $items[76] }} | Check bounds. | PowerShell |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
$values[47] = 5; | if (isset($values[47])) $values[47] = 5; | Check existence. | PHP |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
<person name='output'/> | <person name="output"/> | Double quotes. | XML |
let foo: i32 = "value"; | let foo: &str = "value"; | Type mismatch. | Rust |
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