need help for project

[agitowanijima]

uhm i have a question

#include<iostream.h>
clrscr();
           long factorial(long);
           void main(void) {
                                  long number;
                                  cout<<"Please enter a positive integer ";
                                  cin>>number;
           if(number<0)
                                  cout<<"That is not a positive integer.\n ";
           else
                                  cout<<number<<"factorial is: "<<factorial(number)<<endl;
}
           long factorial(long number) {
           long temp;
           if(number<=1) return 1;
                                  temp=number * factorial(number -1)
           return temp;
}

the problem is i cant think of a way that i can print the output of this program
-after i entered 17
the factorial is in negative sign.

is it possible to run it and enter any digits above 100??

can you help me...pls....tnx

[Ganon11]

The problem is that 17! is a massive number - an int, or even a long int, cannot old that large a number. In order to compute large factorials, you need to mess around with classes or use some built in classes/functions. There are several threads going around with users asking the same question - see if they have found any help that you can use.

As an aside, you should never ever use void main(). It is a nonstandard practice that will not work in, say, my compiler, or my neighbor's compiler, or my professor's compiler, etc. It only works in a select few compilers, because it is flat out wrong. Instead, use int main() and return 0; at the end of your main function. Voila! Now your code works everywhere.

[weaknessforcats]

Also, iostream.h is an obsolete C++ header file. It is the non-ANSI C++ from prior to 1998.

You should be using:

#include <iostream>
using namespace std;