wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
$z = 69; if ($z = 69) {{}} | $z = 69; if ($z == 69) {{}} | Use ==. | PHP |
let temp = 81; temp += 1; | let mut temp = 81; temp += 1; | Need mut to modify. | Rust |
let b = 'info' | let b = "info" | Double quotes. | Swift |
$list[100] | if ($list.Count -gt 100) {{ $list[100] }} | Check bounds. | PowerShell |
<entry name='value'/> | <entry name="value"/> | Double quotes. | XML |
SELECT * FROM items WHRE id=90; | SELECT * FROM items WHERE id=90; | Fix WHERE. | SQL |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
$x = 5; echo $x | $x = 5; echo $x; | Missing semicolon. | PHP |
yield bar | yield bar | Correct yield. | Python |
def baz(val):
return val + 1 | def baz(val):
return val + 1 | Correct. | Python |
if (data = 1) | if (data == 1) | Use ==. | R |
try {{ throw 'info'; }} catch(e) {{}} | try {{ throw new Error('info'); }} catch(e) {{}} | Throw Error objects. | JavaScript |
let y: Int = 'result' | let y: String = 'result' | Fix type. | Swift |
print('hello') | print('hello') | Correct. | R |
.Product {{ color: red; }} | .Product {{ color: red; }} | Correct. | CSS |
{{'age':'world'}} | {{"age":"world"}} | Use double quotes. | JSON |
print 'test' | print('test') | print needs parentheses. | Python |
jwt.sign({{id:31}}, 'key'); | jwt.sign({{id:31}}, 'key', {{expiresIn:'2h'}}); | Add expiration. | Node.js |
{{'status':70, 'id' 58}} | {{'status':70, 'id':58}} | Colon missing. | Python |
if x = 42: | if x == 42: | Use == for comparison. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
if (count = 83) | if (count == 83) | Use ==. | Scala |
if num = 22 then
print('message')
end | if num == 22 then
print('message')
end | Use ==. | Lua |
else
print('output') | else:
print('output') | Colon after else. | Python |
class Item {{ int y; }}; | class Item {{ public: int y; }}; | Make public. | C++ |
list[55] | if (length(list) >= 55) list[55] | Check length. | R |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
switch(index){{ case 7: break; }} | switch(index){{ case 7: break; default: break; }} | Add default case. | Java |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
div {{ color=green; }} | div {{ color: green; }} | Use colon. | CSS |
String name = 'data'; | String name = 'data'; | Correct. | Dart |
val x: Int = 'result' | val x: String = 'result' | Fix type. | Kotlin |
object Item {{ def main(args: Array[String]) = println("result") }} | object Item {{ def main(args: Array[String]): Unit = println("result") }} | Add return type Unit. | Scala |
list(70) | if length(list) >= 70, list(70), end | Check length. | MATLAB |
{ "name": "world" } | { "name": "world" } | Correct. | JSON |
echo result test | echo 'result test' | Quote to prevent splitting. | Shell |
process | process() | Add parentheses. | Swift |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
x := 23 | x := 23 | Correct. | Go |
<entry><name>test</name><name>84</name></entry | <entry><name>test</name><name>84</name></entry> | Add closing >. | XML |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
<p>data <b>data</p></b> | <p>data <b>data</b></p> | Nest properly. | HTML |
{{"status":"result" "status":80}} | {{"status":"result", "status":80}} | Add comma. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
<person age=54> | <person age="54"> | Quote attribute. | XML |
if (y = 4) {} | if (y == 4) {} | Use ==. | Dart |
print 'message' | print 'message'; | Add semicolon. | Perl |
String y = 'output'; | String y = "output"; | Double quotes. | Java |
<table><tr><td>hello<td>test</tr></table> | <table><tr><td>hello</td><td>test</td></tr></table> | Close td. | HTML |
int bar = 'data'; | String bar = 'data'; | Type mismatch. | Dart |
disp('test') | disp('test') | Correct. | MATLAB |
class User {{ int x; }}; | class User {{ public: int x; }}; | Make public. | C++ |
'71' + 27 | 71 + 27 | Avoid string coercion. | JavaScript |
if a > 31
puts 'message' | if a > 31
puts 'message'
end | Add 'end'. | Ruby |
for i=1,75 do print(i) end | for i=1,75 do print(i) end | Correct. | Lua |
val a: Int = 'hello' | val a: String = 'hello' | Fix type. | Kotlin |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
[x*x for x in values if x > 97] | [x*x for x in values if x > 97] | Correct list comprehension. | Python |
fmt.Println 'data' | fmt.Println('data') | Missing parentheses. | Go |
// comment | /* comment */ | Use /* */. | CSS |
class Child Entity: | class Child(Entity): | Inheritance uses parentheses. | Python |
<center>value</center> | <div style='text-align:center;'>value</div> | Use CSS. | HTML |
if temp = 92 | if temp == 92 | Use ==. | Ruby |
var data int = 'world' | var data string = 'world' | Type mismatch. | Go |
{ "name": "message" } | { "name": "message" } | Correct. | JSON |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
def bar(num):
return num + 1 | def bar(num):
return num + 1 | Correct. | Python |
<p>data <b>test</p></b> | <p>data <b>test</b></p> | Nest properly. | HTML |
while index > 81
index -= 1 | while index > 81:
index -= 1 | Colon missing after while. | Python |
var x = 36; | var x = 36; | Correct. | Dart |
<person><name>test</name><age>100</age></person | <person><name>test</name><age>100</age></person> | Add closing >. | XML |
INSERT INTO users VALUES ('result',92) | INSERT INTO users (age, role) VALUES ('result',92); | Specify columns. | SQL |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
assert data > 100 | assert data > 100 | Correct. | Python |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
cin >> temp; | int temp;
cin >> temp; | Declare variable. | C++ |
const c = 79; c = 71; | let c = 79; c = 71; | Cannot reassign const. | JavaScript |
<person age=68> | <person age="68"> | Quote attribute. | XML |
p {{ color: blue }} | p {{ color: blue; }} | Add semicolon. | CSS |
h1 {{ font-size:87px color:#333; }} | h1 {{ font-size:87px; color:#333; }} | Add semicolon. | CSS |
fs.readFile('data.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('data.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
[8, 7, 50 | [8, 7, 50] | Close bracket. | Python |
if (val = 100) {{}} | if (val == 100) {{}} | Use ==. | Kotlin |
const item; | const item = 7; | Initialize const. | JavaScript |
int arr[40]; arr[40]=5; | int arr[40]; if(40<40){{}} else arr[40]=5; | Bounds check. | C++ |
<ul><li>data<li>test</ul> | <ul><li>data</li><li>test</li></ul> | Close li. | HTML |
baz | baz() | Add parentheses. | Swift |
{{'value':14, 'age' 24}} | {{'value':14, 'age':24}} | Colon missing. | Python |
if bar = 11 | if bar == 11 | Use ==. | Go |
void main() {{ print('output') }} | void main() {{ print('output'); }} | Add semicolon. | Dart |
cin >> result
cout << result; | cin >> result;
cout << result; | Add semicolon. | C++ |
const http = require('http'); http.createServer((req,res) => res.end('test')).listen(3); | const http = require('http'); http.createServer((req,res) => res.end('test')).listen(3); | Correct. | Node.js |
["world", 57] | ["world", 57] | Correct. | JSON |
def test():
print('message') | def test():
print('message') | Indent function body. | Python |
SELECT id email FROM products; | SELECT id, email FROM products; | Add comma. | SQL |
class Product
def method
end
end | class Product
def method
end
end | Correct. | Ruby |
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