factorial

How would you write a non-recursive algorithm to calculate factorials?

How would you write a non-recursive algorithm to compute n!. ...

When I calculate a large factorial, why do I get a negative number?

So, simple procedure, calculate a factorial number. Code is as follows. int calcFactorial(int num) { int total = 1; if (num == 0) { return 0; } for (num; num > 0; num--) { total *= num; } return total; } Now, this works fine and dandy (There are certainly quicker and more elegant solutions,...

How is factorial computed?

say there is a function to calculate factorial(n) Does factorial(7) creates 7 function object for each of n from 1 to 7 and use those values when ever necessary (for factorial(8) as like factorial(7)*8) ...

Unable to make a factorial function in AWK

The code #!/usr/bin/awk # Sed and AWK by O'Reilly (p.179) # Example of what should happen: factorial 5 gives # factorial # Enter number: 3 # The factorial of 3 is 6 BEGIN { printf("Enter number: ") } $1 ~ /^[0-9]+$/ { # assign value of $1 to number & fact number = $1 if (number == 0) ...

Unable to get a factorial function to work in C

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 t...

working with very large integers in c#

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 B...

Unable to make a factorial function in Python

My code import sys number=int(sys.argv[1]) if number == 0 fact=1 else fact=number for (x=1; x<number; x++) fact*=x; // mistake probably here print fact I get the error File "factorial.py", line 5 if number == 0 ^ SyntaxError: invalid syntax How can you make a factorial function in Pyt...

Unable to increase AWK's int-limit for factorial

I run the AWK code and I get The factorial of 200 is inf This suggests me that AWK does not use the same int IEEE-standard -module as Python. It seems that AWK's limit is 170!. How can you make AWK understand as large integers as Python? ...

C#: Recursive functions with Lambdas

The below does not compile: Func<int, int> fac = n => (n <= 1) ? 1 : n * fac(n - 1); Local variable 'fac' might not be initialized before accessing How can you make a recursive function with lambdas? [Update] Here are also two links that I found interesting to read: Eric Lippert's "Why does a recursive lambda cause a defini...

Can one know how large a factorial would be before calculating it?

I'm using GMP to calculate very large factorials (e.g. 234234!). Is there any way of knowing, before one does the calculation, how many digits long the result will (or might) be? ...

get the consecutive factors ,c#

hi , i need to solve this question but im stuck at getting the factors , but what i need to do is... A positive number n is consecutive-factored if and only if it has factors, i and j where i > 1, j > 1 and j = i + 1. Write a function named isConsecutiveFactored that returns 1 if its argument is consecutive-factored, otherwise it retur...

Why am I getting two very different results from these two functions

this is copied from http://www.zenspider.com/ZSS/Products/RubyInline/Readme.html, the "home" of rubyinline, adding/moding as indicated in the comments require 'rubygems' #added this, doesn't run otherwise require 'inline' class MyTest def factorial(n) f = 1 n.downto(2) { |x| f *= x } f end inline do |builder| bui...

what's a good way to combinate through a set?

Given a set {a,b,c,d} What's a good way to produce {a,b,c,d,ab,ac,ad,bc,bd,cd,abc,abd,abcd}? A recursive algorithm, I think, but maybe some weird lambda thing would work better. I'm using python. ...

How can I calculate a factorial in C# using a library call?

I need to calculate the factorial of numbers up to around 100! in order to determine if a series of coin flip-style data is random, as per this Wikipedia entry on Bayesian probability. As you can see there, the necessary formula involves 3 factorial calculations (but, interestingly, two of those factorial calculations are calculated alo...

Fast algorithms for computing the factorial

I found this page describing a number of algorithms for computing the factorial. Unfortunately, the explanations are terse and I don't feel like sifting through line after line of source code to understand the basic principles behind the algorithms. Can anybody point me to more detailed descriptions of these (or other fast) algorithms f...

What is the optimal way to implement a small cache in C# to store factorial values?

Hi there, Here's the code I have: =========================== public class Foo { //Class field to store factorial values as those are calculated private static Dictionary<uint, double> _factorialCache; public Foo() { _factorialCache = new Dictionary<uint, double>(); } public double Factorial(uint inpu...

Calculating large factorials in C++

Hi all, I understand this is a classic programming problem and therefore I want to be clear I'm not looking for code as a solution, but would appreciate a push in the right direction. I'm learning C++ and as part of the learning process I'm attempting some programming problems. I'm attempting to write a program which deals with numbers...

how java.bigInteger valueOf works ?

I'm making a project concerned big numbers without BigInteger, BigDecimal etc. I've managed to do all the basics but now I need to add ability to count factorials. My BigNumber stores data as int[] . Here's a sample solution with BigInteger but I can't use it without having the actual value of my number. BigInteger n = BigInteger.O...

Can anyone explain this algorithm for calculating large factorials?

i came across the following program for calculating large factorials(numbers as big as 100).. can anyone explain me the basic idea used in this algorithm?? I need to know just the mathematics implemented in calculating the factorial. #include <cmath> #include <iostream> #include <cstdlib> using namespace std; int main() { unsig...

I'm trying to implement factorial in an xml language.

I'm trying to implement factorial in the xml language of xcerion. <step id="fac"> <alias name="p" value="={$n}*{$p}" /> <alias name="n" value="={$n}-1" /> <operation name="decision"> <when test="'{$n}'>'0'" step="fac" /> </operation> </step> <alias name="p" value="1" /> <alias ...