wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let temp = 46; temp += 1; | let mut temp = 46; temp += 1; | Need mut to modify. | Rust |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
[x*x for x in items if x > 81] | [x*x for x in items if x > 81] | Correct list comprehension. | Python |
$data[8] | if ($data.Count -gt 8) {{ $data[8] }} | Check bounds. | PowerShell |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
SELECT age status FROM items; | SELECT age, status FROM items; | Add comma. | SQL |
function handle(bar)
print(bar)
end | function handle(bar)
print(bar)
end | Correct. | Lua |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
let list=vec![78,3,81]; let first=&list[0]; list.push(8); | let mut list=vec![78,3,81]; let first=list[0]; list.push(8); | Copy instead of reference. | Rust |
for i=1,2 do print(i) end | for i=1,2 do print(i) end | Correct. | Lua |
System.out.println('message') | System.out.println('message'); | Add semicolon. | Java |
val val = 7; val = 37 | var val = 7; val = 37 | Use var for reassignment. | Scala |
local y = 41 | local y = 41 | Correct. | Lua |
print 'value' | print 'value'; | Add semicolon. | Perl |
count = 3 | count=3 | No spaces. | Shell |
function compute(z:string){{return z;}} compute(81); | function compute(z:string){{return z;}} compute('hello'); | Pass correct type. | TypeScript |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
a > 85 & b < 46 | a > 85 and b < 46 | Use 'and' not '&'. | Python |
String index = 'result'; | String index = "result"; | Double quotes. | Java |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
<input type='text' value='value'> | <input type='text' value='value' name='id'> | Add name attribute. | HTML |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
class Person
def method
end
end | class Person
def method
end
end | Correct. | Ruby |
my @arr = (66,61,2); | my @arr = (66,61,2); | Correct. | Perl |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
var x = 52; | var x = 52; | Correct. | Dart |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if c > 31
print('result') | if c > 31:
print('result') | Colon missing after if. | Python |
for (int i=0; i<46; i++) {{}} | for (int i=0; i<46; i++) {{}} | Correct. | Java |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
{{"id":"message" "value":58}} | {{"id":"message", "value":58}} | Add comma. | JSON |
if (b = 59) | if (b == 59) | Use ==. | Scala |
if ($x = 22) | if ($x == 22) | Use ==. | Perl |
def render
puts 'info'
end | def render
puts 'info'
end | Correct. | Ruby |
let val = 'test' | let val = "test" | Double quotes. | Swift |
class = 'world' | class_name = 'world' | 'class' is a keyword. | Python |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
int c = 'hello'; | String c = 'hello'; | Type mismatch. | Dart |
with open('log.txt') as f:
data = f.read() | with open('log.txt') as f:
data = f.read() | Correct. | Python |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
let temp: i32 = "info"; | let temp: &str = "info"; | Type mismatch. | Rust |
if y = 54 | if y == 54 | Use ==. | Go |
<person age=62> | <person age="62"> | Quote attribute. | XML |
{{"name":"world",}} | {{"name":"world"}} | Remove trailing comma. | JSON |
arr(57) | if length(arr) >= 57, arr(57), end | Check length. | MATLAB |
[27, 49, 14 | [27, 49, 14] | Close bracket. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
let mut z=95; let r1=&mut z; let r2=&mut z; | let mut z=95; {{ let r1=&mut z; }} let r2=&mut z; | Only one mutable borrow. | Rust |
const x; | const x = 50; | Initialize const. | JavaScript |
class User {{ int item; }}
obj.item=5; | class User {{ public int item; }}
obj.item=5; | Make field public. | Java |
'82' + 48 | 82 + 48 | Avoid string coercion. | JavaScript |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
let y: number | null = null; y.toFixed(54); | let y: number | null = null; if(y!==null) y.toFixed(54); | Null check. | TypeScript |
count = output | count = 'output' | Quote strings. | Python |
if (a = 85) {{}} | if (a == 85) {{}} | Use ==. | Java |
let text1 = String::from("value"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("value"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
let a: Int = 'test' | let a: String = 'test' | Fix type. | Swift |
class = 'output' | class_name = 'output' | 'class' is a keyword. | Python |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
test | test() | Add parentheses. | Swift |
arr[24] | if (arr.indices.contains(24)) arr[24] | Check index. | Kotlin |
val num = 'data' | val num = "data" | Double quotes. | Kotlin |
UPDATE users SET id='output' WHERE role=81 | UPDATE users SET id='output' WHERE role=81; | Add semicolon. | SQL |
class User {{ int b; }}
obj.b=5; | class User {{ public int b; }}
obj.b=5; | Make field public. | Java |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
<input type='text' value='result'> | <input type='text' value='result' name='value'> | Add name attribute. | HTML |
process | process() | Add parentheses. | Kotlin |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
my @arr = (66,64,93); | my @arr = (66,64,93); | Correct. | Perl |
String count = 'world'; | String count = "world"; | Double quotes. | Java |
local data = 95 | local data = 95 | Correct. | Lua |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
<person age=41> | <person age="41"> | Quote attribute. | XML |
SELECT * FROM users WHRE id=10; | SELECT * FROM users WHERE id=10; | Fix WHERE. | SQL |
<user><name>hello</name><age>26</age></user | <user><name>hello</name><age>26</age></user> | Add closing >. | XML |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
cin >> y
cout << y; | cin >> y;
cout << y; | Add semicolon. | C++ |
cin >> index; | int index;
cin >> index; | Declare variable. | C++ |
var x int | var x int | Correct. | Go |
h1 {{ font-size:39px color:#333; }} | h1 {{ font-size:39px; color:#333; }} | Add semicolon. | CSS |
p {{ color: #333 }} | p {{ color: #333; }} | Add semicolon. | CSS |
echo info hello | echo 'info hello' | Quote to prevent splitting. | Shell |
<hr></hr> | <hr> | Self-closing. | HTML |
if b > 40
print('info') | if b > 40:
print('info') | Colon missing after if. | Python |
[x*x for x in list if x > 48] | [x*x for x in list if x > 48] | Correct list comprehension. | Python |
match c {{ 1 => {{}} }} | match c {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
for i=1,89 do print(i) end | for i=1,89 do print(i) end | Correct. | Lua |
def render(c):
return c + 1 | def render(c):
return c + 1 | Correct. | Python |
fn handle() -> i32 {{ 51 }} | fn handle() -> i32 {{ 51 }} | Correct. | Rust |
{{'title':'info'}} | {{"title":"info"}} | Use double quotes. | JSON |
os.sqrt(94) | import os
os.sqrt(94) | Import module first. | Python |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
index == '93' | index === 93 | Use strict equality. | JavaScript |
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