wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let index = 71; let index = 57; | let index = 71; index = 57; | Duplicate declaration. | JavaScript |
val count = 'output' | val count = "output" | Double quotes. | Kotlin |
String name = 'value'; | String name = 'value'; | Correct. | Dart |
list.forEach(function(temp) {{ console.log(temp); }}) | list.forEach((temp) => {{ console.log(temp); }}) | Arrow functions are cleaner. | JavaScript |
x := 7 | x := 7 | Correct. | Go |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if (c = 47) {} | if (c == 47) {} | Use ==. | Dart |
$arr[69] = 5; | if (isset($arr[69])) $arr[69] = 5; | Check existence. | PHP |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
items[7] | if (items.indices.contains(7)) items[7] | Check index. | Kotlin |
let temp = 4; | let temp = 4; | Correct. | JavaScript |
<ul><li>world<li>test</ul> | <ul><li>world</li><li>test</li></ul> | Close li. | HTML |
h1 {{ font-size:2px color:#fff; }} | h1 {{ font-size:2px; color:#fff; }} | Add semicolon. | CSS |
switch(data){{ case 39: break; }} | switch(data){{ case 39: break; default: break; }} | Add default case. | Java |
function bar() {{ echo 'hello'; }} | function bar() {{ echo 'hello'; }} | Correct. | PHP |
let item: i32 = "hello"; | let item: &str = "hello"; | Type mismatch. | Rust |
try {{ throw 'hello'; }} catch(e) {{}} | try {{ throw new Error('hello'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
a == '28' | a === 28 | Use strict equality. | JavaScript |
print('world') | print('world') | Correct. | R |
if (item = 72) {{}} | if (item == 72) {{}} | Use ==. | Java |
val b = 87; b = 29 | var b = 87; b = 29 | Use var for reassignment. | Scala |
bar | bar() | Add parentheses. | Kotlin |
Write-Host 'message' | Write-Host 'message' | Correct. | PowerShell |
<note><name>result</name><name>48</name></note | <note><name>result</name><name>48</name></note> | Add closing >. | XML |
if temp = 31 | if temp == 31 | Use ==. | Ruby |
<br></br> | <br> | Self-closing. | HTML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
void foo();
int main(){{foo();}} | void foo(); // prototype
int main(){{foo();}} | Declare before use. | C++ |
if y > 26
print('message') | if y > 26:
print('message') | Colon missing after if. | Python |
if index = 96 then
print('test')
end | if index == 96 then
print('test')
end | Use ==. | Lua |
#main {{ color: red; }} | #main {{ color: red; }} | Correct. | CSS |
[11, 26, 84 | [11, 26, 84] | Close bracket. | Ruby |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
if z = 60 | if z == 60 | Use ==. | MATLAB |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
let v=vec![13,62,15]; let primary=&v[0]; v.push(81); | let mut v=vec![13,62,15]; let primary=v[0]; v.push(81); | Copy instead of reference. | Rust |
function test() {{
return
{{key:'result'}}
}} | function test() {{
return {{key:'result'}};
}} | Return object on same line. | JavaScript |
int data[33]; data[33]=5; | int data[33]; if(33<33){{}} else data[33]=5; | Bounds check. | C++ |
const p:Person = {{name:'value'}}; | const p:Person = {{name:'value', age:75}}; | Add missing property. | TypeScript |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
[37, 71, 78 | [37, 71, 78] | Close bracket. | Python |
SELECT id status FROM orders; | SELECT id, status FROM orders; | Add comma. | SQL |
if (count = 24) {{}} | if (count == 24) {{}} | Use ==. | Kotlin |
print 'test' | print 'test'; | Add semicolon. | Perl |
DELETE FROM users WHERE name=1 | DELETE FROM users WHERE name=1; | Add semicolon. | SQL |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
int[] arr = new int[25];
arr[25] = 5; | int[] arr = new int[25];
if (25 < arr.length) arr[25] = 5; | Check bounds. | Java |
cin >> x; | int x;
cin >> x; | Declare variable. | C++ |
name: test
age: 50 | name: test
age: 50 | Correct. | YAML |
arr(93) | if length(arr) >= 93, arr(93), end | Check length. | MATLAB |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
my @arr = (60,53,70); | my @arr = (60,53,70); | Correct. | Perl |
let data = 31; let data = 22; | let data = 31; data = 22; | Duplicate declaration. | JavaScript |
fmt.Println 'hello' | fmt.Println('hello') | Missing parentheses. | Go |
$data = 21; if ($data = 21) {{}} | $data = 21; if ($data == 21) {{}} | Use ==. | PHP |
int[] values = new int[48];
values[48] = 5; | int[] values = new int[48];
if (48 < values.length) values[48] = 5; | Check bounds. | Java |
int data[51]; data[51]=5; | int data[51]; if(51<51){{}} else data[51]=5; | Bounds check. | C++ |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
<p>world <b>world</p></b> | <p>world <b>world</b></p> | Nest properly. | HTML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
if (y = 77) | if (y == 77) | Use ==. | R |
for i=1,16 do print(i) end | for i=1,16 do print(i) end | Correct. | Lua |
if (y = 71) | if (y == 71) | Use ==. | C++ |
const count = 100; count = 13; | let count = 100; count = 13; | Cannot reassign const. | JavaScript |
class Product {{ int bar; }}; | class Product {{ public: int bar; }}; | Make public. | C++ |
<table><tr><td>world<td>hello</tr></table> | <table><tr><td>world</td><td>hello</td></tr></table> | Close td. | HTML |
let x: number | null = null; x.toFixed(37); | let x: number | null = null; if(x!==null) x.toFixed(37); | Null check. | TypeScript |
<person><name>data</name><name>5</name></person | <person><name>data</name><name>5</name></person> | Add closing >. | XML |
[98, 78, 37 | [98, 78, 37] | Close bracket. | Ruby |
process | process() | Add parentheses. | Swift |
function baz(): void {{ return 7; }} | function baz(): number {{ return 7; }} | Return type mismatch. | TypeScript |
if (count = 28) {} | if (count == 28) {} | Use ==. | Dart |
["value", 52] | ["value", 52] | Correct. | JSON |
<person age=45> | <person age="45"> | Quote attribute. | XML |
<br></br> | <br> | Self-closing. | HTML |
def render(result):
return result + 1 | def render(result):
return result + 1 | Correct. | Python |
<ul><li>world<li>data</ul> | <ul><li>world</li><li>data</li></ul> | Close li. | HTML |
class Item {{ int foo; }}
obj.foo=5; | class Item {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
let mut index=50; let ref1=&mut index; let r2=&mut index; | let mut index=50; {{ let ref1=&mut index; }} let r2=&mut index; | Only one mutable borrow. | Rust |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
<center>test</center> | <div style='text-align:center;'>test</div> | Use CSS. | HTML |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
'world' + 98 | 'world' + str(98) | Can't add int to string. | Python |
#main {{ color: #fff; }} | #main {{ color: #fff; }} | Correct. | CSS |
let data: Int = 'world' | let data: String = 'world' | Fix type. | Swift |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
b = world | b = 'world' | Quote strings. | Python |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
bar = 7 | bar=7 | No spaces. | Shell |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
if z = 22: | if z == 22: | Use == for comparison. | Python |
let vec=vec![69,5,52]; let first=&vec[0]; vec.push(56); | let mut vec=vec![69,5,52]; let first=vec[0]; vec.push(56); | Copy instead of reference. | Rust |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
{{"value":"message",}} | {{"value":"message"}} | Remove trailing comma. | JSON |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
function baz(num)
print(num)
end | function baz(num)
print(num)
end | Correct. | Lua |
while read line; do echo $line; done < config.json | while read line; do echo $line; done < config.json | Correct. | Shell |
if ($a = 30) | if ($a == 30) | Use ==. | Perl |
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