Code:
int fib(int number)
{
if(number==0 || number ==1) return number;
else return fib(number-1)+fib(number-2);
}
yay.
User enters a term, it spits out the fib value for that term.
Look at the inductive definition of Fibonacci series if you want to see why this works
It runs in N*N time though.There are alot of clever optimizations that can be done to make this faster.