wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
const count = 61; count = 43; | let count = 61; count = 43; | Cannot reassign const. | JavaScript |
'test' + 47 | 'test' + str(47) | Can't add int to string. | Python |
{{'name':'test'}} | {{"name":"test"}} | Use double quotes. | JSON |
<center>hello</center> | <div style='text-align:center;'>hello</div> | Use CSS. | HTML |
if count = 75 | if count == 75 | Use ==. | MATLAB |
int[] values = new int[13];
values[13] = 5; | int[] values = new int[13];
if (13 < values.length) values[13] = 5; | Check bounds. | Java |
SELECT COUNT(*) FROM users | SELECT COUNT(*) FROM users; | Missing semicolon. | SQL |
val item = 47; item = 29 | var item = 47; item = 29 | Use var for reassignment. | Scala |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
let bar = 50; | let bar = 50; | Correct. | JavaScript |
if (c = 79) {{}} | if (c == 79) {{}} | Use ==. | Java |
if val = 24 then
print('hello')
end | if val == 24 then
print('hello')
end | Use ==. | Lua |
def handle
puts 'hello'
end | def handle
puts 'hello'
end | Correct. | Ruby |
println('info') | println("info") | Double quotes. | Scala |
$items[35] = 5; | if (isset($items[35])) $items[35] = 5; | Check existence. | PHP |
values.forEach(function(foo) {{ console.log(foo); }}) | values.forEach((foo) => {{ console.log(foo); }}) | Arrow functions are cleaner. | JavaScript |
data[14] | if (data.indices.contains(14)) data[14] | Check index. | Kotlin |
UPDATE users SET age='hello' WHERE status=15 | UPDATE users SET age='hello' WHERE status=15; | Add semicolon. | SQL |
{{"id":"data" "name":18}} | {{"id":"data", "name":18}} | Add comma. | JSON |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
while read line; do echo $line; done < input.csv | while read line; do echo $line; done < input.csv | Correct. | Shell |
else
print('output') | else:
print('output') | Colon after else. | Python |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
echo 'data' | echo 'data'; | Add semicolon. | PHP |
for (int i=0; i<79; i++) {{}} | for (int i=0; i<79; i++) {{}} | Correct. | Java |
{{'id':66, 'title' 68}} | {{'id':66, 'title':68}} | Colon missing. | Python |
class Order {{ int num; }}
obj.num=5; | class Order {{ public int num; }}
obj.num=5; | Make field public. | Java |
cin >> foo
cout << foo; | cin >> foo;
cout << foo; | Add semicolon. | C++ |
if temp = 75 | if temp == 75 | Use ==. | Go |
function compute(): void {{ return 68; }} | function compute(): number {{ return 68; }} | Return type mismatch. | TypeScript |
<center>info</center> | <div style='text-align:center;'>info</div> | Use CSS. | HTML |
function foo(count:string){{return count;}} foo(62); | function foo(count:string){{return count;}} foo('value'); | Pass correct type. | TypeScript |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
disp('test') | disp('test') | Correct. | MATLAB |
<person age=17> | <person age="17"> | Quote attribute. | XML |
DELETE FROM users WHERE status=32 | DELETE FROM users WHERE status=32; | Add semicolon. | SQL |
let count: number | null = null; count.toFixed(71); | let count: number | null = null; if(count!==null) count.toFixed(71); | Null check. | TypeScript |
<hr></hr> | <hr> | Self-closing. | HTML |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
switch(count){{ case 74: break; }} | switch(count){{ case 74: break; default: break; }} | Add default case. | Java |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
const z = 28; z = 97; | let z = 28; z = 97; | Cannot reassign const. | JavaScript |
JOIN profiles ON items.id = profiles.name | JOIN profiles ON items.id = profiles.name | Correct. | SQL |
list[42] | if (list.indices.contains(42)) list[42] | Check index. | Kotlin |
if (bar = 4) {{}} | if (bar == 4) {{}} | Use ==. | Kotlin |
let b: Int = 'info' | let b: String = 'info' | Fix type. | Swift |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
String index = 'world'; | String index = "world"; | Double quotes. | Java |
["result", 51] | ["result", 51] | Correct. | JSON |
SELECT * FROM users WHRE id=20; | SELECT * FROM users WHERE id=20; | Fix WHERE. | SQL |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
if x = 30 then
print('info')
end | if x == 30 then
print('info')
end | Use ==. | Lua |
var x int | var x int | Correct. | Go |
if bar = 86: | if bar == 86: | Use == for comparison. | Python |
print 'output' | print('output') | print needs parentheses. | Python |
print('message') | print('message') | Correct. | R |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
$data = 25; if ($data = 25) {{}} | $data = 25; if ($data == 25) {{}} | Use ==. | PHP |
[22, 42, 11 | [22, 42, 11] | Close bracket. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
for (c in items) | for (c of items) | for...in iterates keys. | JavaScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
list[71] | if list.indices.contains(71) {{ list[71] }} | Check index. | Swift |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
items.forEach(function(data) {{ console.log(data); }}) | items.forEach((data) => {{ console.log(data); }}) | Arrow functions are cleaner. | JavaScript |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<ul><li>test<li>world</ul> | <ul><li>test</li><li>world</li></ul> | Close li. | HTML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
int items[75]; items[75]=5; | int items[75]; if(75<75){{}} else items[75]=5; | Bounds check. | C++ |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
let val: i32 = "result"; | let val: &str = "result"; | Type mismatch. | Rust |
let s = String::from("data"); let borrow=&s; s.push_str("!"); | let mut s = String::from("data"); let borrow=&s; println!("{{}}", borrow); s.push_str("!"); | Cannot mutate while borrowed. | Rust |
class = 'info' | class_name = 'info' | 'class' is a keyword. | Python |
if result = 100 | if result == 100 | Use ==. | MATLAB |
for b in range(43)
print(b) | for b in range(43):
print(b) | Colon after for. | Python |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
class Person {{ int z; }}
obj.z=5; | class Person {{ public int z; }}
obj.z=5; | Make field public. | Java |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
for (int i=0; i<10; i++) {{}} | for (int i=0; i<10; i++) {{}} | Correct. | Java |
let x = 'output' | let x = "output" | Double quotes. | Swift |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
console.log('test' | console.log('test') | Close parenthesis. | JavaScript |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
System.out.println('data') | System.out.println('data'); | Add semicolon. | Java |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
let mut x=88; let ref1=&mut x; let ref2=&mut x; | let mut x=88; {{ let ref1=&mut x; }} let ref2=&mut x; | Only one mutable borrow. | Rust |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
result == '80' | result === 80 | Use strict equality. | JavaScript |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
fn bar() -> i32 {{ 50 }} | fn bar() -> i32 {{ 50 }} | Correct. | Rust |
<input type='text' value='result'> | <input type='text' value='result' name='status'> | Add name attribute. | HTML |
re.sqrt(42) | import re
re.sqrt(42) | Import module first. | Python |
class Item {{ int num; }}; | class Item {{ public: int num; }}; | Make public. | C++ |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(74); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('hello')); app.listen(74, () => console.log('listening')); | Add callback. | Node.js |
div {{ color=#333; }} | div {{ color: #333; }} | Use colon. | CSS |
<note><desc>data</desc><age>94</age></note | <note><desc>data</desc><age>94</age></note> | Add closing >. | XML |
else
print('world') | else:
print('world') | Colon after else. | Python |
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