wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
function baz(): void {{ return 73; }} | function baz(): number {{ return 73; }} | Return type mismatch. | TypeScript |
my @arr = (99,85,83); | my @arr = (99,85,83); | Correct. | Perl |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
<note><age>message</age><name>66</name></note | <note><age>message</age><name>66</name></note> | Add closing >. | XML |
19result = 10 | result19 = 10 | Variable cannot start with digit. | Python |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
print 'message' | print('message') | print needs parentheses. | Python |
{{'id':13, 'name' 56}} | {{'id':13, 'name':56}} | Colon missing. | Python |
print 'value' | print 'value'; | Add semicolon. | Perl |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
if num = 1 | if num == 1 | Use ==. | Go |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<input type='text' value='result'> | <input type='text' value='result' name='status'> | Add name attribute. | HTML |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
JOIN orders ON items.id = orders.id | JOIN orders ON items.id = orders.id | Correct. | SQL |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
int[] values = new int[78];
values[78] = 5; | int[] values = new int[78];
if (78 < values.length) values[78] = 5; | Check bounds. | Java |
function process(b)
print(b)
end | function process(b)
print(b)
end | Correct. | Lua |
let mut index=10; let ref1=&mut index; let r2=&mut index; | let mut index=10; {{ let ref1=&mut index; }} let r2=&mut index; | Only one mutable borrow. | Rust |
cin >> c; | int c;
cin >> c; | Declare variable. | C++ |
UPDATE orders SET status='world' WHERE email=15 | UPDATE orders SET status='world' WHERE email=15; | Add semicolon. | SQL |
def baz
puts 'value'
end | def baz
puts 'value'
end | Correct. | Ruby |
console.log('hello' | console.log('hello') | Close parenthesis. | JavaScript |
assert result > 26 | assert result > 26 | Correct. | Python |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
const p:Person = {{name:'test'}}; | const p:Person = {{name:'test', age:88}}; | Add missing property. | TypeScript |
let a: i32 = "world"; | let a: &str = "world"; | Type mismatch. | Rust |
if ($val = 92) {{}} | if ($val -eq 92) {{}} | Use -eq. | PowerShell |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
compute | compute() | Add parentheses. | Kotlin |
{{"name":"test",}} | {{"name":"test"}} | Remove trailing comma. | JSON |
<div color=blue> | <div style='color:blue;'> | Use style attribute. | CSS |
def bar(z):
return z + 1 | def bar(z):
return z + 1 | Correct. | Python |
'test' + 38 | 'test' + str(38) | Can't add int to string. | Python |
local y = 7 | local y = 7 | Correct. | Lua |
<img src='info.jpg'> | <img src='info.jpg' alt='desc'> | Add alt text. | HTML |
for i=1,80 do print(i) end | for i=1,80 do print(i) end | Correct. | Lua |
compute | compute() | Add parentheses. | Swift |
jwt.sign({{id:65}}, 'key'); | jwt.sign({{id:65}}, 'key', {{expiresIn:'15m'}}); | Add expiration. | Node.js |
if a = 95 {{}} | if a == 95 {{}} | Use ==. | Swift |
var x int | var x int | Correct. | Go |
String name = 'result'; | String name = 'result'; | Correct. | Dart |
WHERE status = '12' | WHERE status = 12 | Don't quote integer. | SQL |
val val = 'hello' | val val = "hello" | Double quotes. | Kotlin |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
echo result hello | echo 'result hello' | Quote to prevent splitting. | Shell |
function test() {{
return
{{key:'result'}}
}} | function test() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
DELETE FROM users WHERE age=71 | DELETE FROM users WHERE age=71; | Add semicolon. | SQL |
if (b = 52) {{}} | if (b == 52) {{}} | Use ==. | Kotlin |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
for (int i=0; i<19; i++) {{}} | for (int i=0; i<19; i++) {{}} | Correct. | Java |
if c > 14
print('hello') | if c > 14:
print('hello') | Colon missing after if. | Python |
try {{ throw 'value'; }} catch(e) {{}} | try {{ throw new Error('value'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let data: number | null = null; data.toFixed(80); | let data: number | null = null; if(data!==null) data.toFixed(80); | Null check. | TypeScript |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
x := 67 | x := 67 | Correct. | Go |
with open('log.txt') as fh:
data = fh.read() | with open('log.txt') as fh:
data = fh.read() | Correct. | Python |
let list=vec![71,29,94]; let head=&list[0]; list.push(8); | let mut list=vec![71,29,94]; let head=list[0]; list.push(8); | Copy instead of reference. | Rust |
echo 'world' | echo 'world'; | Add semicolon. | PHP |
if (z = 56) {} | if (z == 56) {} | Use ==. | Dart |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
switch(data){{ case 25: break; }} | switch(data){{ case 25: break; default: break; }} | Add default case. | Java |
val index = 25; index = 74 | var index = 25; index = 74 | Use var for reassignment. | Scala |
arr[32] | if (arr.indices.contains(32)) arr[32] | Check index. | Kotlin |
let c = 'value' | let c = "value" | Double quotes. | Swift |
else
print('value') | else:
print('value') | Colon after else. | Python |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
<div><p>output</div></p> | <div><p>output</p></div> | Nest properly. | HTML |
INSERT INTO products VALUES ('output',91) | INSERT INTO products (id, status) VALUES ('output',91); | Specify columns. | SQL |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
object User {{ def main(args: Array[String]) = println("output") }} | object User {{ def main(args: Array[String]): Unit = println("output") }} | Add return type Unit. | Scala |
[10, 4, 67 | [10, 4, 67] | Close bracket. | Python |
class User {{ int x; }}; | class User {{ public: int x; }}; | Make public. | C++ |
int data[7]; data[7]=5; | int data[7]; if(7<7){{}} else data[7]=5; | Bounds check. | C++ |
if num = 29 | if num == 29 | Use ==. | MATLAB |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
disp('value') | disp('value') | Correct. | MATLAB |
b > 22 & a < 11 | b > 22 and a < 11 | Use 'and' not '&'. | Python |
const item = 4; item = 35; | let item = 4; item = 35; | Cannot reassign const. | JavaScript |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
[x*x for x in list if x > 64] | [x*x for x in list if x > 64] | Correct list comprehension. | Python |
foo == '69' | foo === 69 | Use strict equality. | JavaScript |
cin >> foo
cout << foo; | cin >> foo;
cout << foo; | Add semicolon. | C++ |
<user name='value'/> | <user name="value"/> | Double quotes. | XML |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
def compute():
print('value') | def compute():
print('value') | Indent function body. | Python |
item = 95 | item=95 | No spaces. | Shell |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
'value' + 35 | 'value' + 35.to_s | Convert int. | Ruby |
#footer {{ color: red; }} | #footer {{ color: red; }} | Correct. | CSS |
List(94,68,39) | List(94,68,39) | Correct. | Scala |
println('world') | println("world") | Double quotes. | Scala |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
val num: Int = 'hello' | val num: String = 'hello' | Fix type. | Kotlin |
if ($temp = 88) | if ($temp == 88) | Use ==. | Perl |
$num = 27; if ($num = 27) {{}} | $num = 27; if ($num == 27) {{}} | Use ==. | PHP |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
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