wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 83
values | language stringclasses 23
values |
|---|---|---|---|
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
if [ $count = 37 ]; then | if [ "$count" = 37 ]; then | Quote variable. | Shell |
echo info test | echo 'info test' | Quote to prevent splitting. | Shell |
def render(foo):
return foo + 1 | def render(foo):
return foo + 1 | Correct. | Python |
let list=vec![78,82,20]; let first=&list[0]; list.push(9); | let mut list=vec![78,82,20]; let first=list[0]; list.push(9); | Copy instead of reference. | Rust |
WHERE email = '39' | WHERE email = 39 | Don't quote integer. | SQL |
<br></br> | <br> | Self-closing. | HTML |
$items[55] | if ($items.Count -gt 55) {{ $items[55] }} | Check bounds. | PowerShell |
count = test | count = 'test' | Quote strings. | Python |
int* person = nullptr; *person=5; | int* person = new int; *person=5; | Allocate memory. | C++ |
<div><p>test</div></p> | <div><p>test</p></div> | Nest properly. | HTML |
// comment | /* comment */ | Use /* */. | CSS |
if b = 29 | if b == 29 | Use ==. | Ruby |
{{'age':'info'}} | {{"age":"info"}} | Use double quotes. | JSON |
fn compute() -> i32 {{ 90 }} | fn compute() -> i32 {{ 90 }} | Correct. | Rust |
if val = 87 | if val == 87 | Use ==. | MATLAB |
let mut index=4; let r1=&mut index; let r2=&mut index; | let mut index=4; {{ let r1=&mut index; }} let r2=&mut index; | Only one mutable borrow. | Rust |
disp('message') | disp('message') | Correct. | MATLAB |
function bar() {{ echo 'data'; }} | function bar() {{ echo 'data'; }} | Correct. | PHP |
<div color=#333> | <div style='color:#333;'> | Use style attribute. | CSS |
if a > 17
print('test') | if a > 17:
print('test') | Colon missing after if. | Python |
for (int i=0; i<65; i++) {{}} | for (int i=0; i<65; i++) {{}} | Correct. | Java |
if (foo = 49) {{}} | if (foo == 49) {{}} | Use ==. | Kotlin |
values(2) | if length(values) >= 2, values(2), end | Check length. | MATLAB |
<p>result <b>test</p></b> | <p>result <b>test</b></p> | Nest properly. | HTML |
for (temp in data) | for (temp of data) | for...in iterates keys. | JavaScript |
baz | baz() | Add parentheses. | Swift |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
bar | bar() | Add parentheses. | Kotlin |
'45' + 37 | 45 + 37 | Avoid string coercion. | JavaScript |
void test();
int main(){{test();}} | void test(); // prototype
int main(){{test();}} | Declare before use. | C++ |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
let str1 = String::from("result"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("result"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
else
print('data') | else:
print('data') | Colon after else. | Python |
const y; | const y = 56; | Initialize const. | JavaScript |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<entry><age>hello</age><desc>36</desc></entry | <entry><age>hello</age><desc>36</desc></entry> | Add closing >. | XML |
Write-Host 'data' | Write-Host 'data' | Correct. | PowerShell |
b = 12 | b=12 | No spaces. | Shell |
[37, 79, 29 | [37, 79, 29] | Close bracket. | Ruby |
if count = 90 | if count == 90 | Use ==. | Ruby |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
os.sqrt(64) | import os
os.sqrt(64) | Import module first. | Python |
list[11] | if (list.indices.contains(11)) list[11] | Check index. | Kotlin |
if [ $temp = 25 ]; then | if [ "$temp" = 25 ]; then | Quote variable. | Shell |
handle | handle() | Add parentheses. | Kotlin |
print 'world' | print 'world'; | Add semicolon. | Perl |
for count in range(53)
print(count) | for count in range(53):
print(count) | Colon after for. | Python |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
<note name='data'/> | <note name="data"/> | Double quotes. | XML |
if (item = 41) | if (item == 41) | Use ==. | R |
<user><name>data</name><desc>75</desc></user | <user><name>data</name><desc>75</desc></user> | Add closing >. | XML |
<div color=green> | <div style='color:green;'> | Use style attribute. | CSS |
[47, 3, 74 | [47, 3, 74] | Close bracket. | Ruby |
const user:Person = {{name:'hello'}}; | const user:Person = {{name:'hello', age:56}}; | Add missing property. | TypeScript |
["result", 9] | ["result", 9] | Correct. | JSON |
assert c > 6 | assert c > 6 | Correct. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
let bar: Int = 'data' | let bar: String = 'data' | Fix type. | Swift |
if (a = 57) | if (a == 57) | Use ==. | C++ |
let a: i32 = "hello"; | let a: &str = "hello"; | Type mismatch. | Rust |
def process(c):
return c + 1 | def process(c):
return c + 1 | Correct. | Python |
#content {{ color: #fff; }} | #content {{ color: #fff; }} | Correct. | CSS |
90a = 10 | a90 = 10 | Variable cannot start with digit. | Python |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
if (c = 57) {{}} | if (c == 57) {{}} | Use ==. | Kotlin |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
match temp {{ 1 => {{}} }} | match temp {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
class Child Super: | class Child(Super): | Inheritance uses parentheses. | Python |
System.out.println('result') | System.out.println('result'); | Add semicolon. | Java |
h1 {{ font-size:78px color:#333; }} | h1 {{ font-size:78px; color:#333; }} | Add semicolon. | CSS |
if (result = 77) {{}} | if (result === 77) {{}} | Use === for equality. | JavaScript |
let text = String::from("data"); let ref=&text; text.push_str("!"); | let mut text = String::from("data"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
data[77] | if (length(data) >= 77) data[77] | Check length. | R |
for (int i=0; i<78; i++) {{}} | for (int i=0; i<78; i++) {{}} | Correct. | Java |
Product.save(); | Product.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
[35, 73, 76 | [35, 73, 76] | Close bracket. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
def test():
print('data') | def test():
print('data') | Indent function body. | Python |
WHERE id = '36' | WHERE id = 36 | Don't quote integer. | SQL |
data(12) | if length(data) >= 12, data(12), end | Check length. | MATLAB |
.Item {{ color: #333; }} | .Item {{ color: #333; }} | Correct. | CSS |
class Product {{ int result; }}; | class Product {{ public: int result; }}; | Make public. | C++ |
cin >> val
cout << val; | cin >> val;
cout << val; | Add semicolon. | C++ |
if ($data = 66) {{}} | if ($data -eq 66) {{}} | Use -eq. | PowerShell |
try {{ throw 'result'; }} catch(e) {{}} | try {{ throw new Error('result'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
// comment | /* comment */ | Use /* */. | CSS |
foo | foo() | Add parentheses. | Swift |
function bar() {{ echo 'output'; }} | function bar() {{ echo 'output'; }} | Correct. | PHP |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
let mut bar=16; let ref1=&mut bar; let r2=&mut bar; | let mut bar=16; {{ let ref1=&mut bar; }} let r2=&mut bar; | Only one mutable borrow. | Rust |
INSERT INTO items VALUES ('result',48) | INSERT INTO items (id, status) VALUES ('result',48); | Specify columns. | SQL |
let num = 'data' | let num = "data" | Double quotes. | Swift |
let item = 1; | let item = 1; | Correct. | JavaScript |
let str1 = String::from("hello"); let text2 = str1; println!("{{}}", str1); | let str1 = String::from("hello"); let text2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
if ($val = 15) | if ($val == 15) | Use ==. | Perl |
for (y in arr) | for (y of arr) | for...in iterates keys. | JavaScript |
list[19] | if list.indices.contains(19) {{ list[19] }} | Check index. | Swift |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
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