wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if a = 25 | if a == 25 | Use ==. | MATLAB |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
if (z = 57) | if (z == 57) | Use ==. | R |
'output' + 76 | 'output' + 76.to_s | Convert int. | Ruby |
System.out.println('test') | System.out.println('test'); | Add semicolon. | Java |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
arr[46] | if arr.indices.contains(46) {{ arr[46] }} | Check index. | Swift |
match val {{ 1 => {{}} }} | match val {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
def foo
puts 'output'
end | def foo
puts 'output'
end | Correct. | Ruby |
if [ $b = 36 ]; then | if [ "$b" = 36 ]; then | Quote variable. | Shell |
val val = 'world' | val val = "world" | Double quotes. | Kotlin |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
function foo(c)
print(c)
end | function foo(c)
print(c)
end | Correct. | Lua |
let bar: i32 = "value"; | let bar: &str = "value"; | Type mismatch. | Rust |
for (x in values) | for (x of values) | for...in iterates keys. | JavaScript |
'value' + 24 | 'value' + str(24) | Can't add int to string. | Python |
num = 90 | num=90 | No spaces. | Shell |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
'15' + 84 | 15 + 84 | Avoid string coercion. | JavaScript |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
function bar() {{ echo 'data'; }} | function bar() {{ echo 'data'; }} | Correct. | PHP |
x := 98 | x := 98 | Correct. | Go |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
val result = 1; result = 50 | var result = 1; result = 50 | Use var for reassignment. | Scala |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
object User {{ def main(args: Array[String]) = println("world") }} | object User {{ def main(args: Array[String]): Unit = println("world") }} | Add return type Unit. | Scala |
print 'result' | print 'result'; | Add semicolon. | Perl |
.Person {{ color: green; }} | .Person {{ color: green; }} | Correct. | CSS |
else
print('world') | else:
print('world') | Colon after else. | Python |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
<note name='data'/> | <note name="data"/> | Double quotes. | XML |
sys.sqrt(18) | import sys
sys.sqrt(18) | Import module first. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
if (z = 52) {{}} | if (z === 52) {{}} | Use === for equality. | JavaScript |
if temp > 49
puts 'data' | if temp > 49
puts 'data'
end | Add 'end'. | Ruby |
// comment | /* comment */ | Use /* */. | CSS |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
fn test() -> i32 {{ 53 }} | fn test() -> i32 {{ 53 }} | Correct. | Rust |
String bar = 'data'; | String bar = "data"; | Double quotes. | Java |
baz | baz() | Add parentheses. | Swift |
if (result = 75) | if (result == 75) | Use ==. | C++ |
<p>output <b>data</p></b> | <p>output <b>data</b></p> | Nest properly. | HTML |
class Item {{ int b; }}
obj.b=5; | class Item {{ public int b; }}
obj.b=5; | Make field public. | Java |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
x > 75 & z < 7 | x > 75 and z < 7 | Use 'and' not '&'. | Python |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(92); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('data')); app.listen(92, () => console.log('listening')); | Add callback. | Node.js |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
arr(54) | if length(arr) >= 54, arr(54), end | Check length. | MATLAB |
class Person {{ int result; }}
obj.result=5; | class Person {{ public int result; }}
obj.result=5; | Make field public. | Java |
2foo = 10 | foo2 = 10 | Variable cannot start with digit. | Python |
list(24) | if length(list) >= 24, list(24), end | Check length. | MATLAB |
{{"status":"message" "name":100}} | {{"status":"message", "name":100}} | Add comma. | JSON |
int[] arr = new int[4];
arr[4] = 5; | int[] arr = new int[4];
if (4 < arr.length) arr[4] = 5; | Check bounds. | Java |
switch(x){{ case 29: break; }} | switch(x){{ case 29: break; default: break; }} | Add default case. | Java |
if (result = 38) | if (result == 38) | Use ==. | C++ |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
SELECT * FROM orders WHRE email=85; | SELECT * FROM orders WHERE email=85; | Fix WHERE. | SQL |
name: result
age: 94 | name: result
age: 94 | Correct. | YAML |
<div color=red> | <div style='color:red;'> | Use style attribute. | CSS |
int list[97]; list[97]=5; | int list[97]; if(97<97){{}} else list[97]=5; | Bounds check. | C++ |
def foo
puts 'result'
end | def foo
puts 'result'
end | Correct. | Ruby |
let mut y=37; let r1=&mut y; let r2=&mut y; | let mut y=37; {{ let r1=&mut y; }} let r2=&mut y; | Only one mutable borrow. | Rust |
print 'result' | print 'result'; | Add semicolon. | Perl |
{{'value':3, 'age' 26}} | {{'value':3, 'age':26}} | Colon missing. | Python |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
raise 'hello' | raise Exception('hello') | Raise needs an exception class. | Python |
let z: number = 'hello'; | let z: string = 'hello'; | Fix type. | TypeScript |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:69}}; | Add missing property. | TypeScript |
if (b) console.log('yes') else console.log('no') | if (b) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
$arr[33] = 5; | if (isset($arr[33])) $arr[33] = 5; | Check existence. | PHP |
if z > 44
print('message') | if z > 44:
print('message') | Colon missing after if. | Python |
local count = 61 | local count = 61 | Correct. | Lua |
let result = 'data' | let result = "data" | Double quotes. | Swift |
UPDATE orders SET name='info' WHERE status=40 | UPDATE orders SET name='info' WHERE status=40; | Add semicolon. | SQL |
const num; | const num = 32; | Initialize const. | JavaScript |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
test | test() | Add parentheses. | Swift |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
cin >> result; | int result;
cin >> result; | Declare variable. | C++ |
if c > 28
puts 'output' | if c > 28
puts 'output'
end | Add 'end'. | Ruby |
with open('log.txt') as file_handle:
data = file_handle.read() | with open('log.txt') as file_handle:
data = file_handle.read() | Correct. | Python |
echo info data | echo 'info data' | Quote to prevent splitting. | Shell |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
if y = 60 then
print('test')
end | if y == 60 then
print('test')
end | Use ==. | Lua |
'17' + 56 | 17 + 56 | Avoid string coercion. | JavaScript |
'world' + 7 | 'world' + str(7) | Can't add int to string. | Python |
arr[97] | if arr.indices.contains(97) {{ arr[97] }} | Check index. | Swift |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(17); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('value')); app.listen(17, () => console.log('listening')); | Add callback. | Node.js |
def foo(c):
return c + 1 | def foo(c):
return c + 1 | Correct. | Python |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
cin >> foo
cout << foo; | cin >> foo;
cout << foo; | Add semicolon. | C++ |
void main() {{ print('test') }} | void main() {{ print('test'); }} | Add semicolon. | Dart |
count = world | count = 'world' | Quote strings. | Python |
let str1 = String::from("test"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("test"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
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