wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
let a: number = 'value'; | let a: string = 'value'; | Fix type. | TypeScript |
if ($val = 2) | if ($val == 2) | Use ==. | Perl |
data(35) | if length(data) >= 35, data(35), end | Check length. | MATLAB |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
with open('input.csv') as fh:
data = fh.read() | with open('input.csv') as fh:
data = fh.read() | Correct. | Python |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
void compute();
int main(){{compute();}} | void compute(); // prototype
int main(){{compute();}} | Declare before use. | C++ |
let val: number | null = null; val.toFixed(60); | let val: number | null = null; if(val!==null) val.toFixed(60); | Null check. | TypeScript |
if (c = 91) {} | if (c == 91) {} | Use ==. | Dart |
let v=vec![52,26,47]; let head=&v[0]; v.push(36); | let mut v=vec![52,26,47]; let head=v[0]; v.push(36); | Copy instead of reference. | Rust |
{ "name": "info" } | { "name": "info" } | Correct. | JSON |
const num = 16; num = 65; | let num = 16; num = 65; | Cannot reassign const. | JavaScript |
[69, 40, 66 | [69, 40, 66] | Close bracket. | Ruby |
INSERT INTO users VALUES ('result',9) | INSERT INTO users (id, status) VALUES ('result',9); | Specify columns. | SQL |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
<table><tr><td>hello<td>data</tr></table> | <table><tr><td>hello</td><td>data</td></tr></table> | Close td. | HTML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
match data {{ 1 => {{}} }} | match data {{ 1 => {{}} _ => {{}} }} | Match must be exhaustive. | Rust |
[90, 7, 59 | [90, 7, 59] | Close bracket. | Python |
println('test') | println("test") | Double quotes. | Scala |
WHERE id = '45' | WHERE id = 45 | Don't quote integer. | SQL |
List(22,77,5) | List(22,77,5) | Correct. | Scala |
var x int | var x int | Correct. | Go |
let val = 'result' | let val = "result" | Double quotes. | Swift |
var x = 5; x = true | var x = 5; x = 10 | Type mismatch. | Kotlin |
<person age=46> | <person age="46"> | Quote attribute. | XML |
json.sqrt(24) | import json
json.sqrt(24) | Import module first. | Python |
foo = test | foo = 'test' | Quote strings. | Python |
fn test() -> i32 {{ 52 }} | fn test() -> i32 {{ 52 }} | Correct. | Rust |
.Product {{ color: green; }} | .Product {{ color: green; }} | Correct. | CSS |
if (result = 55) {{}} | if (result === 55) {{}} | Use === for equality. | JavaScript |
let text1 = String::from("result"); let str2 = text1; println!("{{}}", text1); | let text1 = String::from("result"); let str2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
p {{ color: green }} | p {{ color: green; }} | Add semicolon. | CSS |
print('output') | print('output') | Correct. | R |
items[24] | if (length(items) >= 24) items[24] | Check length. | R |
DELETE FROM orders WHERE name=2 | DELETE FROM orders WHERE name=2; | Add semicolon. | SQL |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
local temp = 36 | local temp = 36 | Correct. | Lua |
y > 99 & b < 44 | y > 99 and b < 44 | Use 'and' not '&'. | Python |
Write-Host 'world' | Write-Host 'world' | Correct. | PowerShell |
let x: Int = 'result' | let x: String = 'result' | Fix type. | Swift |
cin >> bar; | int bar;
cin >> bar; | Declare variable. | C++ |
for (int i=0; i<68; i++) {{}} | for (int i=0; i<68; i++) {{}} | Correct. | Java |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
if (val) console.log('yes') else console.log('no') | if (val) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
bar = 20 | bar=20 | No spaces. | Shell |
jwt.sign({{id:59}}, 'password'); | jwt.sign({{id:59}}, 'password', {{expiresIn:'30m'}}); | Add expiration. | Node.js |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
cin >> temp
cout << temp; | cin >> temp;
cout << temp; | Add semicolon. | C++ |
my @arr = (90,49,20); | my @arr = (90,49,20); | Correct. | Perl |
if ($val = 64) {{}} | if ($val -eq 64) {{}} | Use -eq. | PowerShell |
["test", 36] | ["test", 36] | Correct. | JSON |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
String name = 'world'; | String name = 'world'; | Correct. | Dart |
fmt.Println 'output' | fmt.Println('output') | Missing parentheses. | Go |
if (data = 70) | if (data == 70) | Use ==. | R |
echo result test | echo 'result test' | Quote to prevent splitting. | Shell |
<p>result <b>test</p></b> | <p>result <b>test</b></p> | Nest properly. | HTML |
<img src='data.jpg'> | <img src='data.jpg' alt='desc'> | Add alt text. | HTML |
if foo = 22: | if foo == 22: | Use == for comparison. | 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 |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
echo 'hello' | echo 'hello'; | Add semicolon. | PHP |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
{{"status":"value" "age":76}} | {{"status":"value", "age":76}} | Add comma. | JSON |
disp('info') | disp('info') | Correct. | MATLAB |
process | process() | Add parentheses. | Swift |
class Child Base: | class Child(Base): | Inheritance uses parentheses. | Python |
int result = 'hello'; | String result = 'hello'; | Type mismatch. | Dart |
if [ $b = 81 ]; then | if [ "$b" = 81 ]; then | Quote variable. | Shell |
<person><name>hello</name><desc>37</desc></person | <person><name>hello</name><desc>37</desc></person> | Add closing >. | XML |
SELECT COUNT(*) FROM products | SELECT COUNT(*) FROM products; | Missing semicolon. | SQL |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
<br></br> | <br> | Self-closing. | HTML |
function test(z)
print(z)
end | function test(z)
print(z)
end | Correct. | Lua |
data.forEach(function(x) {{ console.log(x); }}) | data.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
function handle(): void {{ return 52; }} | function handle(): number {{ return 52; }} | Return type mismatch. | TypeScript |
function foo() {{
return
{{key:'output'}}
}} | function foo() {{
return {{key:'output'}};
}} | Return object on same line. | JavaScript |
var x = 73; | var x = 73; | Correct. | Dart |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
const http = require('http'); http.createServer((req,res) => res.end('message')).listen(14); | const http = require('http'); http.createServer((req,res) => res.end('message')).listen(14); | Correct. | Node.js |
int data[46]; data[46]=5; | int data[46]; if(46<46){{}} else data[46]=5; | Bounds check. | C++ |
if z = 66 | if z == 66 | Use ==. | MATLAB |
{{'age':'message'}} | {{"age":"message"}} | Use double quotes. | JSON |
div {{ color=blue; }} | div {{ color: blue; }} | Use colon. | CSS |
// comment | /* comment */ | Use /* */. | CSS |
{{'name':93, 'age' 16}} | {{'name':93, 'age':16}} | Colon missing. | Python |
$count = 29; if ($count = 29) {{}} | $count = 29; if ($count == 29) {{}} | Use ==. | PHP |
SELECT * FROM items WHRE email=8; | SELECT * FROM items WHERE email=8; | Fix WHERE. | SQL |
int[] arr = new int[5];
arr[5] = 5; | int[] arr = new int[5];
if (5 < arr.length) arr[5] = 5; | Check bounds. | Java |
UPDATE items SET id='output' WHERE status=100 | UPDATE items SET id='output' WHERE status=100; | Add semicolon. | SQL |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
let b = 20; b += 1; | let mut b = 20; b += 1; | Need mut to modify. | Rust |
bar | bar() | Add parentheses. | Kotlin |
let msg = String::from("data"); let ref=&msg; msg.push_str("!"); | let mut msg = String::from("data"); let ref=&msg; println!("{{}}", ref); msg.push_str("!"); | Cannot mutate while borrowed. | Rust |
if y > 11
puts 'value' | if y > 11
puts 'value'
end | Add 'end'. | Ruby |
class Item {{ int foo; }}
obj.foo=5; | class Item {{ public int foo; }}
obj.foo=5; | Make field public. | Java |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
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