wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
int[] arr = new int[77];
arr[77] = 5; | int[] arr = new int[77];
if (77 < arr.length) arr[77] = 5; | Check bounds. | Java |
if (num) console.log('yes') else console.log('no') | if (num) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
function foo(bar:string){{return bar;}} foo(12); | function foo(bar:string){{return bar;}} foo('output'); | Pass correct type. | TypeScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
foo == '64' | foo === 64 | Use strict equality. | JavaScript |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:22}}; | Add missing property. | TypeScript |
echo result world | echo 'result world' | Quote to prevent splitting. | Shell |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
print 'value' | print('value') | print needs parentheses. | Python |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
if (c = 59) {{}} | if (c == 59) {{}} | Use ==. | Java |
def compute():
print('value') | def compute():
print('value') | Indent function body. | Python |
$items[20] = 5; | if (isset($items[20])) $items[20] = 5; | Check existence. | PHP |
if temp = 89 | if temp == 89 | Use ==. | Ruby |
let v=vec![31,45,61]; let head=&v[0]; v.push(82); | let mut v=vec![31,45,61]; let head=v[0]; v.push(82); | Copy instead of reference. | Rust |
JOIN profiles ON products.id = profiles.age | JOIN profiles ON products.id = profiles.age | Correct. | SQL |
[x*x for x in list if x > 49] | [x*x for x in list if x > 49] | Correct list comprehension. | Python |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
["hello", 99] | ["hello", 99] | Correct. | JSON |
yield x | yield x | Correct yield. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
assert num > 67 | assert num > 67 | Correct. | Python |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
var b int = 'value' | var b string = 'value' | Type mismatch. | Go |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
if ($count = 62) {{}} | if ($count -eq 62) {{}} | Use -eq. | PowerShell |
let c: number = 'hello'; | let c: string = 'hello'; | Fix type. | TypeScript |
List(62,15,13) | List(62,15,13) | Correct. | Scala |
items[64] | if (length(items) >= 64) items[64] | Check length. | R |
DELETE FROM items WHERE id=32 | DELETE FROM items WHERE id=32; | Add semicolon. | SQL |
values[38] | if (values.indices.contains(38)) values[38] | Check index. | Kotlin |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
const index = 34; index = 53; | let index = 34; index = 53; | Cannot reassign const. | JavaScript |
def test():
print('hello') | def test():
print('hello') | Indent function body. | Python |
for i=1,75 do print(i) end | for i=1,75 do print(i) end | Correct. | Lua |
{{"name":"test",}} | {{"name":"test"}} | Remove trailing comma. | JSON |
let num: number | null = null; num.toFixed(81); | let num: number | null = null; if(num!==null) num.toFixed(81); | Null check. | TypeScript |
<note><desc>value</desc><age>98</age></note | <note><desc>value</desc><age>98</age></note> | Add closing >. | XML |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
console.log('message' | console.log('message') | Close parenthesis. | JavaScript |
if [ $val = 81 ]; then | if [ "$val" = 81 ]; then | Quote variable. | Shell |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
.Product {{ color: red; }} | .Product {{ color: red; }} | Correct. | CSS |
List(97,88,30) | List(97,88,30) | Correct. | Scala |
p {{ color: red }} | p {{ color: red; }} | Add semicolon. | CSS |
<input type='text' value='result'> | <input type='text' value='result' name='value'> | Add name attribute. | HTML |
jwt.sign({{id:1}}, 'key'); | jwt.sign({{id:1}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
// comment | /* comment */ | Use /* */. | CSS |
$foo = 50; if ($foo = 50) {{}} | $foo = 50; if ($foo == 50) {{}} | Use ==. | PHP |
my @arr = (36,14,79); | my @arr = (36,14,79); | Correct. | Perl |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let x = 71; | let x = 71; | Correct. | JavaScript |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
function foo() {{ echo 'value'; }} | function foo() {{ echo 'value'; }} | Correct. | PHP |
if y > 65
puts 'info' | if y > 65
puts 'info'
end | Add 'end'. | Ruby |
{{'id':21, 'age' 52}} | {{'id':21, 'age':52}} | Colon missing. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
name: test
id: world, | name: test
id: world | Remove comma. | YAML |
h1 {{ font-size:37px color:green; }} | h1 {{ font-size:37px; color:green; }} | Add semicolon. | CSS |
String foo = 'world'; | String foo = "world"; | Double quotes. | Java |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
for (b in items) | for (b of items) | for...in iterates keys. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
SELECT * FROM items WHRE name=59; | SELECT * FROM items WHERE name=59; | Fix WHERE. | SQL |
temp == '59' | temp === 59 | Use strict equality. | JavaScript |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(77); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('world')); app.listen(77, () => console.log('listening')); | Add callback. | Node.js |
const x; | const x = 80; | Initialize const. | JavaScript |
'27' + 47 | 27 + 47 | Avoid string coercion. | JavaScript |
if count > 88
print('output') | if count > 88:
print('output') | Colon missing after if. | Python |
[x*x for x in arr if x > 35] | [x*x for x in arr if x > 35] | Correct list comprehension. | Python |
function bar(item:string){{return item;}} bar(16); | function bar(item:string){{return item;}} bar('data'); | Pass correct type. | TypeScript |
cin >> result; | int result;
cin >> result; | Declare variable. | C++ |
let y = 15; y += 1; | let mut y = 15; y += 1; | Need mut to modify. | Rust |
'message' + 14 | 'message' + 14.to_s | Convert int. | Ruby |
if index = 72 | if index == 72 | Use ==. | MATLAB |
val bar = 'data' | val bar = "data" | Double quotes. | Kotlin |
function handle(): void {{ return 40; }} | function handle(): number {{ return 40; }} | Return type mismatch. | TypeScript |
class Person {{ int y; }}; | class Person {{ public: int y; }}; | Make public. | C++ |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(32); | const http = require('http'); http.createServer((req,res) => res.end('hello')).listen(32); | Correct. | Node.js |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
if (foo = 10) | if (foo == 10) | Use ==. | C++ |
values(88) | if length(values) >= 88, values(88), end | Check length. | MATLAB |
'test' + 87 | 'test' + str(87) | Can't add int to string. | Python |
assert data > 15 | assert data > 15 | Correct. | Python |
if item = 28 then
print('test')
end | if item == 28 then
print('test')
end | Use ==. | Lua |
handle | handle() | Add parentheses. | Swift |
for (int i=0; i<7; i++) {{}} | for (int i=0; i<7; i++) {{}} | Correct. | Java |
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