함수 factorial() 문서 원본 보기

[[분류: 팩토리얼]]
==개요==
;factorial()
;FACT()
* [[팩토리얼]]을 구하는 함수

==테스트케이스==
{{z컬럼3|
* factorial(0) {{=}} 1
* factorial(1) {{=}} 1
* factorial(2) {{=}} 2
* factorial(3) {{=}} 6
* factorial(4) {{=}} 24
* factorial(5) {{=}} 120
* factorial(6) {{=}} 720
* factorial(7) {{=}} 5040
* factorial(8) {{=}} 40320
* factorial(9) {{=}} 362880
* factorial(10) {{=}} 3628800
}}

==C==
{{참고|C factorial()}}
<syntaxhighlight lang='c' run>
#include <stdio.h>

long long factorial(int num) {
    if (num == 0) return 1;
    return num * factorial(num - 1);
}

int main() {
    printf("%lld\n", factorial(9));  // 362880
    printf("%lld\n", factorial(12)); // 479001600
}
</syntaxhighlight>

==Excel==
{{참고|엑셀 FACT()}}
[[분류: Excel]]
<syntaxhighlight lang='php'>
=FACT(4)
// 24
</syntaxhighlight>

==Java==
[[분류: Java]]
<syntaxhighlight lang='java' run>
public class MyClass {
    static int fact(int n) {
        int res = 1;
        for(int i=2; i<=n; i++) res *= i;
        return res;
    }
	public static void main(String args[]){
		System.out.println(fact(1)); // 1
		System.out.println(fact(2)); // 2
		System.out.println(fact(4)); // 24
		System.out.println(fact(8)); // 40320
		System.out.println(fact(9)); // 362880
		System.out.println(fact(10)); // 3628800
		System.out.println(fact(11)); // 39916800
		System.out.println(fact(12)); // 479001600
		System.out.println(fact(13)); // 1932053504 (wrong value, ≠ 6227020800)
		System.out.println(fact(14)); // 1278945280 (wrong value, ≠ 87178291200)
	}
}
</syntaxhighlight>

==JavaScript==
{{참고|자바스크립트 factorial()}}
[[분류: JavaScript]]
<syntaxhighlight lang='JavaScript'>
function factorial(n) {
    var result = 1;
    for(var i=2; i<=n; i++) result *= i;
    return result;
}
</syntaxhighlight>

==Lua==
{{참고|Lua factorial()}}
[[분류: Lua]]
<syntaxhighlight lang='lua'>
function factorial(n)
    if n == 0 then
        return 1
    end
    return n * factorial(n - 1)
end
</syntaxhighlight>

== Perl ==
[[category: Perl]]
<syntaxhighlight lang='perl'>
sub factorial {
	my ($x, $result) = (shift, 1);
	$result *= $_ for (2 ... $x);
	return $result;
}
</syntaxhighlight>

==PHP==
{{참고|PHP factorial()}}
[[분류: PHP]]
{{소스헤더|반복}}
<syntaxhighlight lang='php'>
function factorial($x) {
	$result = 1;
	for($i=2; $i<=$x; $i++) $result *= $i;
	return $result;
}
echo factorial(4);
# 24
</syntaxhighlight>
{{소스헤더|재귀}}
<syntaxhighlight lang='php'>
function factorial($n) {
	if( $n <= 1 ) return 1;
	return $n * factorial($n-1);
}
echo factorial(4);
# 24
</syntaxhighlight>

==Python==
{{참고|파이썬 factorial()}}
[[category: Python]]
<syntaxhighlight lang='Python'>
from math import factorial
print( factorial(4) )
</syntaxhighlight>
<syntaxhighlight lang='Python'>
def factorial(x):
    result = 1
    for i in range(2,x+1):
        result *= i
    return result
</syntaxhighlight>

==R==
{{참고|R factorial()}}
<syntaxhighlight lang='r'>
factorial(0)   ## [1] 1
factorial(1)   ## [1] 1
factorial(2)   ## [1] 2
factorial(3)   ## [1] 6
factorial(4)   ## [1] 24
factorial(5)   ## [1] 120
factorial(6)   ## [1] 720
factorial(10)  ## [1] 3628800
factorial(100) ## [1] 9.332622e+157
factorial(-1)  ## [1] NaN
</syntaxhighlight>

==같이 보기==
* [[팩토리얼]]
* [[함수 nPr()]]
* [[함수 nCr()]]