recursive function

[scuzzo]

I am trying to write the body of a recursive function in pseudo code but it has been years since I've done any coding.
a,b,a+b,a+2b,2a+3b,3a+5b...
is the pattern. I see that this looks like a fibonacci sequence where the previous term is added to the current term to get the next term but I can't express this in any kind of code. Can anyone help me please.

[nerdinator]

void DoIt(int a,int b)
{
	static int LastTerm=a;
	static int CurrentTerm=b;
	int Temp=CurrentTerm;
	CurrentTerm=LastTerm+CurrentTerm;
	LastTerm=Temp;
	cout<<CurrentTerm<<endl;
	string s;
	cin>>s;
	if(s=="yes")
	{
		DoIt(a,b);
	}
}

I think it should work.
It doesn't print the first two numbers.

[alanjhd08]

Say you have a function DoIt(a,b,n), where n is the term in the series you want to find.

Then, maybe;

If n = 1, return a.
If n =2, return b;
If n = 3, return a + b
If n = 4 or more, return DoIt(b,a+b,n-1)

[OReubens]

Actually it is a fibonacci sequence, but with set start values rather than 0,1 as start values.

the shorthand results would be:

myfib(0,a,b) = a
myfib(1,a,b) = b
myfib(n,a,b) = myfib(n-1,a,b) + myfib(n-2,a,b)


In actual code:

int myfib(int TermNum, int a, int b)
{
   if (nTermNum==0)
      return a;
  else if (nTermNum==1)
    return b;
  else
       return myfib(nTermNum-1, a, b) + myfib(nTermNum-2, a, b);
}

The above of course is somewhat less than efficient since it'll split into 2 calls retracing back each time through the recursive sequence, this is the same problem as when you would program the actual fibonacci sequence recursively. It's typically better to solve this linearly without recursion.

int myfib(int TermNum, int a, int b)
{
       if (nTermNum==0)
      return a;
  else if (nTermNum==1)
    return b;
  else
  {
      do 
      {
          nTermNum--;
          int next=a+b;
          a=b;
          b=next;
      }
      while (nTermNum>1)

      return b;
  }
}