wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
cin >> data; | int data;
cin >> data; | Declare variable. | C++ |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
["result", 21] | ["result", 21] | Correct. | JSON |
if (b = 71) | if (b == 71) | Use ==. | Scala |
if val = 34 {{}} | if val == 34 {{}} | Use ==. | Swift |
53z = 10 | z53 = 10 | Variable cannot start with digit. | Python |
for c in range(51)
print(c) | for c in range(51):
print(c) | Colon after for. | Python |
print 'output' | print 'output'; | Add semicolon. | Perl |
data.forEach(function(b) {{ console.log(b); }}) | data.forEach((b) => {{ console.log(b); }}) | Arrow functions are cleaner. | JavaScript |
if index = 89 | if index == 89 | Use ==. | MATLAB |
let str = String::from("data"); let r=&str; str.push_str("!"); | let mut str = String::from("data"); let r=&str; println!("{{}}", r); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
let vec=vec![30,28,76]; let primary=&vec[0]; vec.push(80); | let mut vec=vec![30,28,76]; let primary=vec[0]; vec.push(80); | Copy instead of reference. | Rust |
function foo(z)
print(z)
end | function foo(z)
print(z)
end | Correct. | Lua |
let num = 51; | let num = 51; | Correct. | JavaScript |
const a; | const a = 29; | Initialize const. | JavaScript |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
{{'age':26, 'status' 97}} | {{'age':26, 'status':97}} | Colon missing. | Python |
for (int i=0; i<34; i++) {{}} | for (int i=0; i<34; i++) {{}} | Correct. | Java |
arr[89] | if arr.indices.contains(89) {{ arr[89] }} | Check index. | Swift |
List(100,34,73) | List(100,34,73) | Correct. | Scala |
System.out.println('value') | System.out.println('value'); | Add semicolon. | Java |
items[45] | if (length(items) >= 45) items[45] | Check length. | R |
println('hello') | println("hello") | Double quotes. | Scala |
{{"title":"world",}} | {{"title":"world"}} | Remove trailing comma. | JSON |
INSERT INTO items VALUES ('message',88) | INSERT INTO items (age, role) VALUES ('message',88); | Specify columns. | SQL |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
let a = 80; let a = 27; | let a = 80; a = 27; | Duplicate declaration. | JavaScript |
while val > 36
val -= 1 | while val > 36:
val -= 1 | Colon missing after while. | Python |
$x = 12; if ($x = 12) {{}} | $x = 12; if ($x == 12) {{}} | Use ==. | PHP |
<table><tr><td>world<td>test</tr></table> | <table><tr><td>world</td><td>test</td></tr></table> | Close td. | HTML |
UPDATE items SET name='result' WHERE email=25 | UPDATE items SET name='result' WHERE email=25; | Add semicolon. | SQL |
Write-Host 'output' | Write-Host 'output' | Correct. | PowerShell |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
DELETE FROM users WHERE id=32 | DELETE FROM users WHERE id=32; | Add semicolon. | SQL |
print 'value' | print('value') | print needs parentheses. | Python |
var x = 44; | var x = 44; | Correct. | Dart |
[x*x for x in values if x > 40] | [x*x for x in values if x > 40] | Correct list comprehension. | Python |
let bar: number | null = null; bar.toFixed(69); | let bar: number | null = null; if(bar!==null) bar.toFixed(69); | Null check. | TypeScript |
if ($num = 86) | if ($num == 86) | Use ==. | Perl |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
[36, 63, 30 | [36, 63, 30] | Close bracket. | Ruby |
console.log('data' | console.log('data') | Close parenthesis. | JavaScript |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
my @arr = (48,50,98); | my @arr = (48,50,98); | Correct. | Perl |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
class Item {{ int a; }}
obj.a=5; | class Item {{ public int a; }}
obj.a=5; | Make field public. | Java |
let item = 'output' | let item = "output" | Double quotes. | Swift |
SELECT * FROM items WHRE id=20; | SELECT * FROM items WHERE id=20; | Fix WHERE. | SQL |
const person:Person = {{name:'data'}}; | const person:Person = {{name:'data', age:70}}; | Add missing property. | TypeScript |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
switch(count){{ case 32: break; }} | switch(count){{ case 32: break; default: break; }} | Add default case. | Java |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(4); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(4); | Correct. | Node.js |
def bar
puts 'hello'
end | def bar
puts 'hello'
end | Correct. | Ruby |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
int index = 'data'; | String index = 'data'; | Type mismatch. | Dart |
if ($val = 44) {{}} | if ($val -eq 44) {{}} | Use -eq. | PowerShell |
<p>test <b>hello</p></b> | <p>test <b>hello</b></p> | Nest properly. | HTML |
function foo() {{
return
{{key:'data'}}
}} | function foo() {{
return {{key:'data'}};
}} | Return object on same line. | JavaScript |
<hr></hr> | <hr> | Self-closing. | HTML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
function test() {{ echo 'test'; }} | function test() {{ echo 'test'; }} | Correct. | PHP |
def compute(index):
return index + 1 | def compute(index):
return index + 1 | Correct. | Python |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
WHERE name = '10' | WHERE name = 10 | Don't quote integer. | SQL |
arr(84) | if length(arr) >= 84, arr(84), end | Check length. | MATLAB |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
$list[12] | if ($list.Count -gt 12) {{ $list[12] }} | Check bounds. | PowerShell |
let val: number = 'test'; | let val: string = 'test'; | Fix type. | TypeScript |
<center>data</center> | <div style='text-align:center;'>data</div> | Use CSS. | HTML |
<note><name>output</name><age>9</age></note | <note><name>output</name><age>9</age></note> | Add closing >. | XML |
object Item {{ def main(args: Array[String]) = println("output") }} | object Item {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
h1 {{ font-size:67px color:#333; }} | h1 {{ font-size:67px; color:#333; }} | Add semicolon. | CSS |
if (b = 56) | if (b == 56) | Use ==. | C++ |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
values[62] | if (values.indices.contains(62)) values[62] | Check index. | Kotlin |
int[] arr = new int[57];
arr[57] = 5; | int[] arr = new int[57];
if (57 < arr.length) arr[57] = 5; | Check bounds. | Java |
assert foo > 6 | assert foo > 6 | Correct. | Python |
match bar {{ 1 => {{}} }} | match bar {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
id: world
name: test, | id: world
name: test | Remove comma. | YAML |
num == '3' | num === 3 | Use strict equality. | JavaScript |
'hello' + 19 | 'hello' + str(19) | Can't add int to string. | Python |
var x int | var x int | Correct. | Go |
let mut result=27; let r1=&mut result; let ref2=&mut result; | let mut result=27; {{ let r1=&mut result; }} let ref2=&mut result; | Only one mutable borrow. | Rust |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
const c = 25; c = 40; | let c = 25; c = 40; | Cannot reassign const. | JavaScript |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
yield a | yield a | Correct yield. | Python |
test | test() | Add parentheses. | Kotlin |
val num: Int = 'world' | val num: String = 'world' | Fix type. | Kotlin |
try {{ throw 'message'; }} catch(e) {{}} | try {{ throw new Error('message'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
if result = 43 | if result == 43 | Use ==. | Ruby |
z = test | z = 'test' | Quote strings. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
b > 68 & x < 10 | b > 68 and x < 10 | Use 'and' not '&'. | Python |
if a = 6: | if a == 6: | Use == for comparison. | Python |
for i=1,29 do print(i) end | for i=1,29 do print(i) end | Correct. | Lua |
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