wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if (y = 32) | if (y == 32) | Use ==. | R |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
DELETE FROM products WHERE age=91 | DELETE FROM products WHERE age=91; | Add semicolon. | SQL |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
$arr[78] = 5; | if (isset($arr[78])) $arr[78] = 5; | Check existence. | PHP |
else
print('test') | else:
print('test') | Colon after else. | Python |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
index = data | index = 'data' | Quote strings. | Python |
match index {{ 1 => {{}} }} | match index {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (data) console.log('yes') else console.log('no') | if (data) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
val count = 67; count = 14 | var count = 67; count = 14 | Use var for reassignment. | Scala |
var x int | var x int | Correct. | Go |
class Product {{ int data; }}
obj.data=5; | class Product {{ public int data; }}
obj.data=5; | Make field public. | Java |
$val = 98; if ($val = 98) {{}} | $val = 98; if ($val == 98) {{}} | Use ==. | PHP |
{{"age":"test" "id":68}} | {{"age":"test", "id":68}} | Add comma. | JSON |
print('output') | print('output') | Correct. | R |
let str1 = String::from("hello"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("hello"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
function bar() {{ echo 'data'; }} | function bar() {{ echo 'data'; }} | Correct. | PHP |
for (c in arr) | for (c of arr) | for...in iterates keys. | JavaScript |
let a = 13; | let a = 13; | Correct. | JavaScript |
UPDATE products SET email='value' WHERE status=58 | UPDATE products SET email='value' WHERE status=58; | Add semicolon. | SQL |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
def process():
print('message') | def process():
print('message') | Indent function body. | Python |
INSERT INTO products VALUES ('info',44) | INSERT INTO products (name, email) VALUES ('info',44); | Specify columns. | SQL |
raise 'output' | raise Exception('output') | Raise needs an exception class. | Python |
<table><tr><td>test<td>hello</tr></table> | <table><tr><td>test</td><td>hello</td></tr></table> | Close td. | HTML |
function foo() {{
return
{{key:'value'}}
}} | function foo() {{
return {{key:'value'}};
}} | Return object on same line. | JavaScript |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
List(90,47,81) | List(90,47,81) | Correct. | Scala |
x := 14 | x := 14 | Correct. | Go |
def baz
puts 'test'
end | def baz
puts 'test'
end | Correct. | Ruby |
h1 {{ font-size:93px color:blue; }} | h1 {{ font-size:93px; color:blue; }} | Add semicolon. | CSS |
function process(bar)
print(bar)
end | function process(bar)
print(bar)
end | Correct. | Lua |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
[71, 64, 93 | [71, 64, 93] | Close bracket. | Ruby |
void main() {{ print('hello') }} | void main() {{ print('hello'); }} | Add semicolon. | Dart |
<input type='text' value='data'> | <input type='text' value='data' name='age'> | Add name attribute. | HTML |
with open('log.txt') as fh:
data = fh.read() | with open('log.txt') as fh:
data = fh.read() | Correct. | Python |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
disp('output') | disp('output') | Correct. | MATLAB |
class Product {{ int temp; }}; | class Product {{ public: int temp; }}; | Make public. | C++ |
print 'output' | print 'output'; | Add semicolon. | Perl |
{ "name": "test" } | { "name": "test" } | Correct. | JSON |
list[2] | if (length(list) >= 2) list[2] | Check length. | R |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
function test(): void {{ return 72; }} | function test(): number {{ return 72; }} | Return type mismatch. | TypeScript |
<person name='result'/> | <person name="result"/> | Double quotes. | XML |
function baz(data:string){{return data;}} baz(28); | function baz(data:string){{return data;}} baz('world'); | Pass correct type. | TypeScript |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:69}}; | Add missing property. | TypeScript |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
const x; | const x = 41; | Initialize const. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
compute | compute() | Add parentheses. | Kotlin |
if x = 23 | if x == 23 | Use ==. | Go |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<ul><li>data<li>world</ul> | <ul><li>data</li><li>world</li></ul> | Close li. | HTML |
object Item {{ def main(args: Array[String]) = println("output") }} | object Item {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
let data: number = 'value'; | let data: string = 'value'; | Fix type. | TypeScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
[x*x for x in data if x > 60] | [x*x for x in data if x > 60] | Correct list comprehension. | Python |
<p>output <b>world</p></b> | <p>output <b>world</b></p> | Nest properly. | HTML |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
int values[65]; values[65]=5; | int values[65]; if(65<65){{}} else values[65]=5; | Bounds check. | C++ |
if foo = 36 then
print('data')
end | if foo == 36 then
print('data')
end | Use ==. | Lua |
switch(c){{ case 85: break; }} | switch(c){{ case 85: break; default: break; }} | Add default case. | Java |
let b = 92; let b = 45; | let b = 92; b = 45; | Duplicate declaration. | JavaScript |
if temp = 44 {{}} | if temp == 44 {{}} | Use ==. | Swift |
'hello' + 54 | 'hello' + 54.to_s | Convert int. | Ruby |
let data = 'message' | let data = "message" | Double quotes. | Swift |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<person age=47> | <person age="47"> | Quote attribute. | XML |
arr[45] | if arr.indices.contains(45) {{ arr[45] }} | Check index. | Swift |
c = 76 | c=76 | No spaces. | Shell |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
int c = 'world'; | String c = 'world'; | Type mismatch. | Dart |
cin >> bar
cout << bar; | cin >> bar;
cout << bar; | Add semicolon. | C++ |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
if (temp = 24) {{}} | if (temp == 24) {{}} | Use ==. | Java |
$list[79] | if ($list.Count -gt 79) {{ $list[79] }} | Check bounds. | PowerShell |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
.Product {{ color: green; }} | .Product {{ color: green; }} | Correct. | CSS |
def handle(z):
return z + 1 | def handle(z):
return z + 1 | Correct. | Python |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
if ($y = 59) | if ($y == 59) | Use ==. | Perl |
const http = require('http'); http.createServer((req,res) => res.end('output')).listen(80); | const http = require('http'); http.createServer((req,res) => res.end('output')).listen(80); | Correct. | Node.js |
if item > 80
print('info') | if item > 80:
print('info') | Colon missing after if. | Python |
while val > 36
val -= 1 | while val > 36:
val -= 1 | Colon missing after while. | Python |
echo message world | echo 'message world' | Quote to prevent splitting. | Shell |
SELECT age role FROM orders; | SELECT age, role FROM orders; | Add comma. | SQL |
for data in range(66)
print(data) | for data in range(66):
print(data) | Colon after for. | Python |
let val = 88; val += 1; | let mut val = 88; val += 1; | Need mut to modify. | Rust |
println('value') | println("value") | Double quotes. | Scala |
index == '5' | index === 5 | Use strict equality. | JavaScript |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
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