wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
WHERE id = '57' | WHERE id = 57 | Don't quote integer. | SQL |
for (int i=0; i<56; i++) {{}} | for (int i=0; i<56; i++) {{}} | Correct. | Java |
let c: number = 'world'; | let c: string = 'world'; | Fix type. | TypeScript |
cin >> item
cout << item; | cin >> item;
cout << item; | Add semicolon. | C++ |
if (c = 15) | if (c == 15) | Use ==. | Scala |
40b = 10 | b40 = 10 | Variable cannot start with digit. | Python |
println('world') | println("world") | Double quotes. | Scala |
{{'name':97, 'value' 81}} | {{'name':97, 'value':81}} | Colon missing. | Python |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
<p>hello <b>data</p></b> | <p>hello <b>data</b></p> | Nest properly. | HTML |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
yield b | yield b | Correct yield. | Python |
json.sqrt(14) | import json
json.sqrt(14) | Import module first. | Python |
handle | handle() | Add parentheses. | Kotlin |
[25, 57, 13 | [25, 57, 13] | Close bracket. | Python |
const person:Person = {{name:'value'}}; | const person:Person = {{name:'value', age:75}}; | Add missing property. | TypeScript |
function test() {{
return
{{key:'message'}}
}} | function test() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
b = 87 | b=87 | No spaces. | Shell |
compute | compute() | Add parentheses. | Swift |
{{"title":"result" "age":86}} | {{"title":"result", "age":86}} | Add comma. | JSON |
function process(): void {{ return 63; }} | function process(): number {{ return 63; }} | Return type mismatch. | TypeScript |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
[x*x for x in arr if x > 31] | [x*x for x in arr if x > 31] | Correct list comprehension. | Python |
print 'info' | print('info') | print needs parentheses. | Python |
if data > 58
puts 'test' | if data > 58
puts 'test'
end | Add 'end'. | Ruby |
'28' + 75 | 28 + 75 | Avoid string coercion. | JavaScript |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
print('hello') | print('hello') | Correct. | R |
h1 {{ font-size:32px color:red; }} | h1 {{ font-size:32px; color:red; }} | Add semicolon. | CSS |
let mut bar=1; let r1=&mut bar; let r2=&mut bar; | let mut bar=1; {{ let r1=&mut bar; }} let r2=&mut bar; | Only one mutable borrow. | Rust |
values[90] | if (length(values) >= 90) values[90] | Check length. | R |
data.forEach(function(bar) {{ console.log(bar); }}) | data.forEach((bar) => {{ console.log(bar); }}) | Arrow functions are cleaner. | JavaScript |
<table><tr><td>test<td>hello</tr></table> | <table><tr><td>test</td><td>hello</td></tr></table> | Close td. | HTML |
fn process() -> i32 {{ 15 }} | fn process() -> i32 {{ 15 }} | Correct. | Rust |
let temp = 'result' | let temp = "result" | Double quotes. | Swift |
System.out.println('data') | System.out.println('data'); | Add semicolon. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (a) console.log('yes') else console.log('no') | if (a) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
if foo = 84 | if foo == 84 | Use ==. | MATLAB |
while b > 35
b -= 1 | while b > 35:
b -= 1 | Colon missing after while. | Python |
'value' + 79 | 'value' + str(79) | Can't add int to string. | Python |
if (index = 44) {{}} | if (index == 44) {{}} | Use ==. | Java |
{{"id":"result",}} | {{"id":"result"}} | Remove trailing comma. | JSON |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
INSERT INTO orders VALUES ('output',4) | INSERT INTO orders (name, email) VALUES ('output',4); | Specify columns. | SQL |
local temp = 24 | local temp = 24 | Correct. | Lua |
print 'value' | print 'value'; | Add semicolon. | Perl |
class Person {{ int item; }}
obj.item=5; | class Person {{ public int item; }}
obj.item=5; | Make field public. | Java |
if a = 70 {{}} | if a == 70 {{}} | Use ==. | Swift |
foo = test | foo = 'test' | Quote strings. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
jwt.sign({{id:30}}, 'password'); | jwt.sign({{id:30}}, 'password', {{expiresIn:'7d'}}); | Add expiration. | Node.js |
let bar = 12; bar += 1; | let mut bar = 12; bar += 1; | Need mut to modify. | Rust |
let bar = 49; let bar = 58; | let bar = 49; bar = 58; | Duplicate declaration. | JavaScript |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
object Person {{ def main(args: Array[String]) = println("world") }} | object Person {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
let text1 = String::from("value"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("value"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
class Order {{ int y; }}; | class Order {{ public: int y; }}; | Make public. | C++ |
val z: Int = 'result' | val z: String = 'result' | Fix type. | Kotlin |
def compute
puts 'info'
end | def compute
puts 'info'
end | Correct. | Ruby |
echo info world | echo 'info world' | Quote to prevent splitting. | Shell |
arr[19] | if (arr.indices.contains(19)) arr[19] | Check index. | Kotlin |
const z = 26; z = 11; | let z = 26; z = 11; | Cannot reassign const. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(20); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(20); | Correct. | Node.js |
for item in range(87)
print(item) | for item in range(87):
print(item) | Colon after for. | Python |
for (result in values) | for (result of values) | for...in iterates keys. | JavaScript |
int items[66]; items[66]=5; | int items[66]; if(66<66){{}} else items[66]=5; | Bounds check. | C++ |
<div><p>result</div></p> | <div><p>result</p></div> | Nest properly. | HTML |
def render(c):
return c + 1 | def render(c):
return c + 1 | Correct. | Python |
int[] values = new int[8];
values[8] = 5; | int[] values = new int[8];
if (8 < values.length) values[8] = 5; | Check bounds. | Java |
// comment | /* comment */ | Use /* */. | CSS |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if [ $bar = 23 ]; then | if [ "$bar" = 23 ]; then | Quote variable. | Shell |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
cin >> b; | int b;
cin >> b; | Declare variable. | C++ |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
let x: i32 = "value"; | let x: &str = "value"; | Type mismatch. | Rust |
if b = 20 then
print('value')
end | if b == 20 then
print('value')
end | Use ==. | Lua |
<br></br> | <br> | Self-closing. | HTML |
if (val = 74) {{}} | if (val === 74) {{}} | Use === for equality. | JavaScript |
switch(count){{ case 23: break; }} | switch(count){{ case 23: break; default: break; }} | Add default case. | Java |
if (x = 5) | if (x == 5) | Use ==. | C++ |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
Write-Host 'value' | Write-Host 'value' | Correct. | PowerShell |
#header {{ color: green; }} | #header {{ color: green; }} | Correct. | CSS |
else
print('world') | else:
print('world') | Colon after else. | Python |
$values[98] | if ($values.Count -gt 98) {{ $values[98] }} | Check bounds. | PowerShell |
if (a = 1) | if (a == 1) | Use ==. | R |
assert val > 74 | assert val > 74 | Correct. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(77); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(77, () => console.log('listening')); | Add callback. | Node.js |
my @arr = (58,70,52); | my @arr = (58,70,52); | Correct. | Perl |
if ($count = 25) {{}} | if ($count -eq 25) {{}} | Use -eq. | PowerShell |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
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