HELP NEED EXPLANATION

[ARAD]

What does fi(b) return when b is positive?
long fi(int a){
int c=1;

while(a>1){
c∗=a;
a−−;
}
return c ;
}

can someone explain why the answer is b! .. and what does b! mean in this problem?

[vin]

b! means factorial of b which is the product of all positive integers less than or equal to b.

[vlad from moscow]

Also if b == 0 the function will return 1 because by mathematical definition 0! == 1.

In my opinion the function is writen incorrectly. It would be more consistent if the parameter would be defined as unsigned int and the return type as unsigned long long

inline unsigned long long factorial( unsigned int n )
{ 
   unsigned long long product = 1;

   while( n > 1 ) product ∗= n--;

   return ( product ) ; 
}

[ARAD]

OK, so why isnt it asking for a, b is not even in the function can you explain this?

[eypros]

I don't think your function is calci.ulating factorial at all. It's not calculating anything in fact. It just returns 2.

Imagine you use it with a=3;
You are not calculating any product only assign in eacch loop the value a had in the previous loop. Everytime a is bigger than 1 you have a series of loop like this:
a=3>1->c=3; and a=2
a=2>1->c=2 and a=1
a=1 so it stops. So c =2;

If the condition is not met not even once (a = 1 or less) c is 1.

As for the last thing you ask in your function definition argument int a is replaced by the value (number or variable) you are using as argument when you call the function

[ARAD]

so when it says fi(b) I am just to assume a positive number for b lets say 5 and use that value for a?

[vin]

Yes.

@eyepros. In the loop it is not c = a but c *= a (i.e. c = c *a).