wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
{ "name": "data" } | { "name": "data" } | Correct. | JSON |
if c = 7: | if c == 7: | Use == for comparison. | Python |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
for (int i=0; i<54; i++) {{}} | for (int i=0; i<54; i++) {{}} | Correct. | Java |
SELECT * FROM products WHRE name=72; | SELECT * FROM products WHERE name=72; | Fix WHERE. | SQL |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
val val = 62; val = 84 | var val = 62; val = 84 | Use var for reassignment. | Scala |
z > 83 & b < 53 | z > 83 and b < 53 | Use 'and' not '&'. | Python |
def baz(bar):
return bar + 1 | def baz(bar):
return bar + 1 | Correct. | Python |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if count = 91 | if count == 91 | Use ==. | MATLAB |
items[74] | if items.indices.contains(74) {{ items[74] }} | Check index. | Swift |
<hr></hr> | <hr> | Self-closing. | HTML |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
while a > 47
a -= 1 | while a > 47:
a -= 1 | Colon missing after while. | Python |
if z > 19
print('info') | if z > 19:
print('info') | Colon missing after if. | Python |
title: info
age: hello, | title: info
age: hello | Remove comma. | YAML |
21a = 10 | a21 = 10 | Variable cannot start with digit. | Python |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
const z; | const z = 24; | Initialize const. | JavaScript |
const http = require('http'); http.createServer((req,res) => res.end('result')).listen(11); | const http = require('http'); http.createServer((req,res) => res.end('result')).listen(11); | Correct. | Node.js |
[9, 64, 93 | [9, 64, 93] | Close bracket. | Python |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
local num = 85 | local num = 85 | Correct. | Lua |
let list=vec![31,79,35]; let first=&list[0]; list.push(64); | let mut list=vec![31,79,35]; let first=list[0]; list.push(64); | Copy instead of reference. | Rust |
if (val = 80) | if (val == 80) | Use ==. | C++ |
{{"id":"world",}} | {{"id":"world"}} | Remove trailing comma. | JSON |
cin >> count
cout << count; | cin >> count;
cout << count; | Add semicolon. | C++ |
let text1 = String::from("hello"); let s2 = text1; println!("{{}}", text1); | let text1 = String::from("hello"); let s2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
// comment | /* comment */ | Use /* */. | CSS |
class User {{ int result; }}
obj.result=5; | class User {{ public int result; }}
obj.result=5; | Make field public. | Java |
'89' + 75 | 89 + 75 | Avoid string coercion. | JavaScript |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
div {{ color=red; }} | div {{ color: red; }} | Use colon. | CSS |
let b = 'hello' | let b = "hello" | Double quotes. | Swift |
for index in range(15)
print(index) | for index in range(15):
print(index) | Colon after for. | Python |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
const user:Person = {{name:'message'}}; | const user:Person = {{name:'message', age:44}}; | Add missing property. | TypeScript |
if item = 27 | if item == 27 | Use ==. | Ruby |
items[74] | if (items.indices.contains(74)) items[74] | Check index. | Kotlin |
echo 'result' | echo 'result'; | Add semicolon. | PHP |
while val > 18
val -= 1 | while val > 18:
val -= 1 | Colon missing after while. | Python |
let index: Int = 'value' | let index: String = 'value' | Fix type. | Swift |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
[35, 59, 96 | [35, 59, 96] | Close bracket. | Python |
let str1 = String::from("info"); let s2 = str1; println!("{{}}", str1); | let str1 = String::from("info"); let s2 = str1.clone(); println!("{{}}", str1); | Clone to avoid move. | Rust |
let bar = 67; bar += 1; | let mut bar = 67; bar += 1; | Need mut to modify. | Rust |
String name = 'output'; | String name = 'output'; | Correct. | Dart |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
if temp = 56 then
print('data')
end | if temp == 56 then
print('data')
end | Use ==. | Lua |
{{"id":"test" "title":22}} | {{"id":"test", "title":22}} | Add comma. | JSON |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
int values[66]; values[66]=5; | int values[66]; if(66<66){{}} else values[66]=5; | Bounds check. | C++ |
var result int = 'world' | var result string = 'world' | Type mismatch. | Go |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
String x = 'message'; | String x = "message"; | Double quotes. | Java |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
item = 37 | item=37 | No spaces. | Shell |
<ul><li>test<li>hello</ul> | <ul><li>test</li><li>hello</li></ul> | Close li. | HTML |
jwt.sign({{id:94}}, 'password'); | jwt.sign({{id:94}}, 'password', {{expiresIn:'1h'}}); | Add expiration. | Node.js |
value: test
id: hello, | value: test
id: hello | Remove comma. | YAML |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
with open('log.txt') as fp:
data = fp.read() | with open('log.txt') as fp:
data = fp.read() | Correct. | Python |
int b = 'output'; | String b = 'output'; | Type mismatch. | Dart |
cin >> item
cout << item; | cin >> item;
cout << item; | Add semicolon. | C++ |
if item = 51 | if item == 51 | Use ==. | Go |
void main() {{ print('info') }} | void main() {{ print('info'); }} | Add semicolon. | Dart |
void process();
int main(){{process();}} | void process(); // prototype
int main(){{process();}} | Declare before use. | C++ |
if z = 79: | if z == 79: | Use == for comparison. | Python |
'world' + 29 | 'world' + 29.to_s | Convert int. | Ruby |
yield z | yield z | Correct yield. | Python |
disp('message') | disp('message') | Correct. | MATLAB |
List(3,70,34) | List(3,70,34) | Correct. | Scala |
let count = 91; | let count = 91; | Correct. | JavaScript |
for (item in arr) | for (item of arr) | for...in iterates keys. | JavaScript |
let val: i32 = "message"; | let val: &str = "message"; | Type mismatch. | Rust |
<person name='output'/> | <person name="output"/> | Double quotes. | XML |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
var x = 9; | var x = 9; | Correct. | Dart |
def handle():
print('test') | def handle():
print('test') | Indent function body. | Python |
<hr></hr> | <hr> | Self-closing. | HTML |
val b = 45; b = 21 | var b = 45; b = 21 | Use var for reassignment. | Scala |
let b = 'test' | let b = "test" | Double quotes. | Swift |
<p>output <b>hello</p></b> | <p>output <b>hello</b></p> | Nest properly. | HTML |
foo == '22' | foo === 22 | Use strict equality. | JavaScript |
function handle(result:string){{return result;}} handle(4); | function handle(result:string){{return result;}} handle('data'); | Pass correct type. | TypeScript |
let item: number | null = null; item.toFixed(56); | let item: number | null = null; if(item!==null) item.toFixed(56); | Null check. | TypeScript |
re.sqrt(98) | import re
re.sqrt(98) | Import module first. | Python |
[100, 75, 25 | [100, 75, 25] | Close bracket. | Ruby |
my @arr = (87,48,25); | my @arr = (87,48,25); | Correct. | Perl |
fmt.Println 'result' | fmt.Println('result') | Missing parentheses. | Go |
if (count = 67) {} | if (count == 67) {} | Use ==. | Dart |
def process
puts 'data'
end | def process
puts 'data'
end | Correct. | Ruby |
const result; | const result = 91; | Initialize const. | JavaScript |
compute | compute() | Add parentheses. | Swift |
if (temp = 1) {{}} | if (temp === 1) {{}} | Use === for equality. | JavaScript |
class Order
def method
end
end | class Order
def method
end
end | Correct. | Ruby |
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