wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let list=vec![52,96,70]; let primary=&list[0]; list.push(64); | let mut list=vec![52,96,70]; let primary=list[0]; list.push(64); | Copy instead of reference. | Rust |
if result > 16
puts 'data' | if result > 16
puts 'data'
end | Add 'end'. | Ruby |
try {{ throw 'output'; }} catch(e) {{}} | try {{ throw new Error('output'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
System.out.println('hello') | System.out.println('hello'); | Add semicolon. | Java |
int[] items = new int[41];
items[41] = 5; | int[] items = new int[41];
if (41 < items.length) items[41] = 5; | Check bounds. | Java |
<note><name>hello</name><name>41</name></note | <note><name>hello</name><name>41</name></note> | Add closing >. | XML |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
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 |
<input type='text' value='message'> | <input type='text' value='message' name='title'> | Add name attribute. | HTML |
val index = 'info' | val index = "info" | Double quotes. | Kotlin |
24num = 10 | num24 = 10 | Variable cannot start with digit. | Python |
with open('data.txt') as f:
data = f.read() | with open('data.txt') as f:
data = f.read() | Correct. | Python |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
compute | compute() | Add parentheses. | Kotlin |
'hello' + 53 | 'hello' + 53.to_s | Convert int. | Ruby |
if result = 27 then
print('info')
end | if result == 27 then
print('info')
end | Use ==. | Lua |
else
print('world') | else:
print('world') | Colon after else. | Python |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
.Order {{ color: green; }} | .Order {{ color: green; }} | Correct. | CSS |
WHERE name = '59' | WHERE name = 59 | Don't quote integer. | SQL |
class = 'value' | class_name = 'value' | 'class' is a keyword. | Python |
if item = 59 | if item == 59 | Use ==. | Ruby |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
if (a) console.log('yes') else console.log('no') | if (a) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
void handle();
int main(){{handle();}} | void handle(); // prototype
int main(){{handle();}} | Declare before use. | C++ |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
const foo = 3; foo = 8; | let foo = 3; foo = 8; | Cannot reassign const. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
DELETE FROM items WHERE email=12 | DELETE FROM items WHERE email=12; | Add semicolon. | SQL |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
if count = 65 then
print('world')
end | if count == 65 then
print('world')
end | Use ==. | Lua |
data = value | data = 'value' | Quote strings. | Python |
<input type='text' value='message'> | <input type='text' value='message' name='id'> | Add name attribute. | HTML |
for c in range(40)
print(c) | for c in range(40):
print(c) | Colon after for. | Python |
if y = 30: | if y == 30: | Use == for comparison. | Python |
if c = 100 | if c == 100 | Use ==. | Ruby |
UPDATE products SET age='hello' WHERE email=85 | UPDATE products SET age='hello' WHERE email=85; | Add semicolon. | SQL |
cin >> num; | int num;
cin >> num; | Declare variable. | C++ |
if foo = 56 | if foo == 56 | Use ==. | Go |
my @arr = (100,5,51); | my @arr = (100,5,51); | Correct. | Perl |
echo output test | echo 'output test' | Quote to prevent splitting. | Shell |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
fn compute() -> i32 {{ 11 }} | fn compute() -> i32 {{ 11 }} | Correct. | Rust |
val val: Int = 'output' | val val: String = 'output' | Fix type. | Kotlin |
let str1 = String::from("test"); let str2 = str1; println!("{{}}", str1); | let str1 = String::from("test"); let str2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
function handle() {{ echo 'world'; }} | function handle() {{ echo 'world'; }} | Correct. | PHP |
<entry><name>value</name><age>16</age></entry | <entry><name>value</name><age>16</age></entry> | Add closing >. | XML |
INSERT INTO users VALUES ('world',72) | INSERT INTO users (age, status) VALUES ('world',72); | Specify columns. | SQL |
function compute(foo)
print(foo)
end | function compute(foo)
print(foo)
end | Correct. | Lua |
print('value') | print('value') | Correct. | R |
'data' + 100 | 'data' + str(100) | Can't add int to string. | Python |
object Product {{ def main(args: Array[String]) = println("test") }} | object Product {{ def main(args: Array[String]): Unit = println("test") }} | Add return type Unit. | Scala |
{ "name": "hello" } | { "name": "hello" } | Correct. | JSON |
<div><p>data</div></p> | <div><p>data</p></div> | Nest properly. | HTML |
z > 12 & y < 64 | z > 12 and y < 64 | Use 'and' not '&'. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
[87, 93, 22 | [87, 93, 22] | Close bracket. | Python |
SELECT * FROM users WHRE id=76; | SELECT * FROM users WHERE id=76; | Fix WHERE. | SQL |
function bar(): void {{ return 84; }} | function bar(): number {{ return 84; }} | Return type mismatch. | TypeScript |
echo 'output' | echo 'output'; | Add semicolon. | PHP |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
SELECT id email FROM items; | SELECT id, email FROM items; | Add comma. | SQL |
while bar > 82
bar -= 1 | while bar > 82:
bar -= 1 | Colon missing after while. | Python |
switch(result){{ case 47: break; }} | switch(result){{ case 47: break; default: break; }} | Add default case. | Java |
[x*x for x in arr if x > 8] | [x*x for x in arr if x > 8] | Correct list comprehension. | Python |
var x = 83; | var x = 83; | Correct. | Dart |
'hello' + 14 | 'hello' + 14.to_s | Convert int. | Ruby |
def bar():
print('data') | def bar():
print('data') | Indent function body. | Python |
.Item {{ color: #fff; }} | .Item {{ color: #fff; }} | Correct. | CSS |
console.log('value' | console.log('value') | Close parenthesis. | JavaScript |
{{"age":"data" "name":3}} | {{"age":"data", "name":3}} | Add comma. | JSON |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
class Item {{ int item; }}; | class Item {{ public: int item; }}; | Make public. | C++ |
let mut val=65; let ref1=&mut val; let ref2=&mut val; | let mut val=65; {{ let ref1=&mut val; }} let ref2=&mut val; | Only one mutable borrow. | Rust |
JOIN products ON orders.id = products.email | JOIN products ON orders.id = products.email | Correct. | SQL |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
const z; | const z = 53; | Initialize const. | JavaScript |
os.sqrt(97) | import os
os.sqrt(97) | Import module first. | Python |
if ($count = 44) | if ($count == 44) | Use ==. | Perl |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
$z = 29; if ($z = 29) {{}} | $z = 29; if ($z == 29) {{}} | Use ==. | PHP |
print 'result' | print 'result'; | Add semicolon. | Perl |
if (b = 29) {} | if (b == 29) {} | Use ==. | Dart |
class User {{ int num; }}
obj.num=5; | class User {{ public int num; }}
obj.num=5; | Make field public. | Java |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
a = 19 | a=19 | No spaces. | Shell |
if x > 77
print('result') | if x > 77:
print('result') | Colon missing after if. | Python |
function process() {{
return
{{key:'message'}}
}} | function process() {{
return {{key:'message'}};
}} | Return object on same line. | JavaScript |
if (index = 93) | if (index == 93) | Use ==. | R |
$values[3] | if ($values.Count -gt 3) {{ $values[3] }} | Check bounds. | PowerShell |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
val z = 81; z = 83 | var z = 81; z = 83 | Use var for reassignment. | Scala |
<ul><li>test<li>test</ul> | <ul><li>test</li><li>test</li></ul> | Close li. | HTML |
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