Programming Forums > Application Development > C++

stopplayingamez · Apr 6th, 2005, 6:29 PM

Hey guys I'm wondering how I could convert this to one that computes 3^n - 2^n....that is 3 to the power n minus 2 to the power n. I understand you can't use ^ for power in c++ is that right..I'm coming from a Java background this is kinda new to me. So i'm wondering how to convert this factorial to the function above....

(Toggle Plain Text)

#include<iostream>
using namespace std;

template <int n> struct Fac // general case n! = n*(n-1)!
{
	enum { result = n * Fac<n-1>::result }; // constant
};
template <> struct Fac<0> // base case 0! = 1
{
enum { result = 1 }; // constant
};
int main()
{
// Fac<c>::result is now a compile-time constant!
cout << Fac<5>::result << endl; // = 5! = 120
cout << Fac<10>::result << endl; // = 10! = 3628800
cout << Fac<0>::result << endl; // = 0! = 1
}

Ooble · Apr 6th, 2005, 7:02 PM

To find the power of something, you use the pow function, found in math.h. Here's an example: http://www.cplusplus.com/ref/cmath/pow.html.

stopplayingamez · Apr 6th, 2005, 7:32 PM

(Toggle Plain Text)

#include<iostream>
using namespace std;

template <int n> struct Fac // general case n! = n*(n-1)!
{
	enum { result = 3 ^ n - 2 ^ n}; // constant
};

int main()
{
// Fac<c>::result is now a compile-time constant!
cout << Fac<5>::result << endl; 
cout << Fac<10>::result << endl; 
cout << Fac<0>::result << endl; 
}

OK what now??

Apr 6th, 2005, 6:29 PM	#1
stopplayingamez Newbie Join Date: Mar 2005 Posts: 11 Rep Power: 0	FActorial Conv. Progr Hey guys I'm wondering how I could convert this to one that computes 3^n - 2^n....that is 3 to the power n minus 2 to the power n. I understand you can't use ^ for power in c++ is that right..I'm coming from a Java background this is kinda new to me. So i'm wondering how to convert this factorial to the function above.... (Toggle Plain Text) #include<iostream> using namespace std; template <int n> struct Fac // general case n! = n(n-1)! { enum { result = n Fac<n-1>::result }; // constant }; template <> struct Fac<0> // base case 0! = 1 { enum { result = 1 }; // constant }; int main() { // Fac<c>::result is now a compile-time constant! cout << Fac<5>::result << endl; // = 5! = 120 cout << Fac<10>::result << endl; // = 10! = 3628800 cout << Fac<0>::result << endl; // = 0! = 1 } #include<iostream> using namespace std; template <int n> struct Fac // general case n! = n(n-1)! { enum { result = n Fac<n-1>::result }; // constant }; template <> struct Fac<0> // base case 0! = 1 { enum { result = 1 }; // constant }; int main() { // Fac<c>::result is now a compile-time constant! cout << Fac<5>::result << endl; // = 5! = 120 cout << Fac<10>::result << endl; // = 10! = 3628800 cout << Fac<0>::result << endl; // = 0! = 1 }

Apr 6th, 2005, 7:02 PM	#2
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	To find the power of something, you use the pow function, found in math.h. Here's an example: http://www.cplusplus.com/ref/cmath/pow.html. __________________ Me :: You :: Them

Apr 6th, 2005, 7:32 PM	#3
stopplayingamez Newbie Join Date: Mar 2005 Posts: 11 Rep Power: 0	(Toggle Plain Text) #include<iostream> using namespace std; template <int n> struct Fac // general case n! = n(n-1)! { enum { result = 3 ^ n - 2 ^ n}; // constant }; int main() { // Fac<c>::result is now a compile-time constant! cout << Fac<5>::result << endl; cout << Fac<10>::result << endl; cout << Fac<0>::result << endl; } #include<iostream> using namespace std; template <int n> struct Fac // general case n! = n(n-1)! { enum { result = 3 ^ n - 2 ^ n}; // constant }; int main() { // Fac<c>::result is now a compile-time constant! cout << Fac<5>::result << endl; cout << Fac<10>::result << endl; cout << Fac<0>::result << endl; } OK what now??

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Programming Forums > Application Development > C++

FActorial Conv. Progr