example 6_3.cpp

data+structures+using+c的源码

//Chapter 6: Fibonacci Number

#include <iostream>

using namespace std;

int rFibNum(int a, int b, int n);

int main()
{
   int firstFibNum;
   int secondFibNum;
   int nth;

   cout<<"Enter the first Fibonacci number: ";
   cin>>firstFibNum;
   cout<<endl;

   cout<<"Enter the second Fibonacci number: ";
   cin>>secondFibNum;
   cout<<endl;

   cout<<"Enter the position of the desired Fibonacci number: ";
   cin>>nth;
   cout<<endl;

   cout<<"The Fibonacci number at position "<<nth<<" is: "
	 << rFibNum(firstFibNum, secondFibNum, nth)<<endl;

   return 0;
}

int rFibNum(int a, int b, int n)
{
	if(n == 1)
		return a;
	else if(n == 2)
			return b;
	else
	    return rFibNum(a, b, n - 1) + rFibNum(a, b, n - 2);
}