factorial

问题 We all know the program for this int fact(int n) { if(n==0) return(1); return(n*fact(n-1)); } But what is not clear to me is how the inner thing is happening? How is it calculating 5*4*3*2*1 (if n is 5) Please give a clear explanation on this. Thanks..... 回答1: Mathematically, the recursive definition of factorial can be expressed recursively like so (from Wikipedia): Consider how this works for n = 3 , using == to mean equivalence: 3! == 2! * 3 == (1! * 2) * 3 == ((1) * 2) * 3 This can be

问题 I cannot get the following code to work. #include <stdio.h> // I am not sure whethere I should void here or not. int main() { // when the first bug is solved, I put here arg[0]. It should be // similar command line parameter as args[0] in Java. int a=3; int b; b = factorial(a); // bug seems to be here, since the %1i seems to work only in fprintf printf("%1i", b); return 0; } int factorial(int x) { int i; for(i=1; i<x; i++) x *= i; return x; } How can you get the code to work? 回答1: AInitak

问题 I'm currently taking a course on Free Code Camp and it's asking me return a factorial for any given number. However, I'm kind of stuck on the question (please forgive me, math isn't my strong point, haha). Here's what it asks: If the integer is represented with the letter n, a factorial is the product of all positive integers less than or equal to n. Factorials are often represented with the shorthand notation n! For example: 5! = 1 * 2 * 3 * 4 * 5 = 120f And here's the starting code:

问题 I need to obtain a progressive word combination of a string. E.g. "this is string" Output: "this is string" "this is" "this string" "is string" "this" "is" "string" Do you know similar algorithm? (I need it in php language) Thanks ;) 回答1: This is a simple code solution to your problem. I concatenate each string recoursively to the remaining ones in the array. $string = "this is a string"; $strings = explode(' ', $string); // print result print_r(concat($strings, "")); // delivers result as

问题 Does anybody know of a way I can calculate very large integers in c# I am trying to calculate the factorial of numbers e.g. 5! = 5*4*3*2*1 = 120 with small numbers this is not a problem but trying to calculate the factorial of the bigest value of a unsigned int which is 4,294,967,295 it doesn't seem possible. I have looked into the BigInteger class but it doesn't seem to do what I need any help would be greatly appreciated 回答1: 4294967295! = 10^(10^10.597) ~ 10^(40000000000) This value

问题 This is my program, but for really large numbers like 100,000, it works very slowly, is there any option to optimize? import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = in.nextInt(); BigInteger sum = BigInteger.valueOf(1); for (BigInteger i = BigInteger.valueOf(n); i.compareTo(BigInteger.ZERO) > 0; i = i.subtract(BigInteger.ONE)) { sum = sum.multiply(i); } System.out.println(sum); } }

问题 I'm trying to get the factorial value of number 66 , but my method resulting me an output 0 . But whenever I try to get the factorial of 5 , it is resulting me an output 120 . Could anyone please tell me why? public static int factorial(int n) { if (n == 1) return n; return n * factorial(n - 1); } 回答1: Sure - factorials get very big, very fast. You're overflowing the bounds of int very quickly... and at some point you'll have multiplied by enough factors to get an overflow to 0, which will

问题 I have been using this function for calculating factorial numbers in JavaScript: var f = []; function factorial (n) { if (n == 0 || n == 1) return 1; if (f[n] > 0) return f[n]; return f[n] = factorial(n-1) * n; } All seemed to be going well until I tried the number 500 . It returned infinity . Is there a way that I can prevent infinity as an answer? Thank you. 回答1: You indeed need to use bignumbers. With math.js you can do: // configure math.js to work with enough precision to do our

问题 @echo off if %1.==. ( echo Missing parameter! Try passing the number as a parameter like 'factorial 10' without the quotes. goto end ) setlocal enabledelayedexpansion set /a count=0 set /a temp=0 set /a digits=1 set /a array1=1 for /L %%i IN (2,1,%1) do ( set /a temp=0 for /L %%j IN ( 1,1,!digits! ) do ( set /a temp=!temp!+!array%%j!*%%i set /a array%%j=!temp!%%10 set /a temp=!temp!/10 ) set /a index=!digits!+1 for /L %%v IN (!index!,1,!index! ) do ( if !temp! NEQ 0 ( set /a array!index!=

问题 I am new to Python and currently reading Python 3 for absolute beginner and face following problem. I would like to calculate factorial with procedure. request user to input an non negative number n then use for loop to calculate factorial and the code is like that: N = input("Please input factorial you would like to calculate: ") ans = 1 for i in range(1,N+1,1): ans = ans*i print(ans) while i would like to add a feature to check whether input number N is non-negative number. like: if N !=