Problem Description
Your objective for this question is to develop a program which will generate a fibbonacci number. The fibbonacci function is defined as such:
f(0) = 0
f(1) = 1
f(n) = f(n-1) + f(n-2)
Your program should be able to handle values of n in the range 0 to 50.
Input
Each test case consists of one integer n in a single line where 0≤n≤50. The input is terminated by -1.
Output
Print out the answer in a single line for each test case.
Hint
Note:you can use 64bit integer: __int64
#include <iostream>
#include <ctype.h>
using namespace std;
int n;
__int64 last_but_one,last;
__int64 cur;
int main()
{
while(cin>>n&&n>=0)
{
if(n==0)
{
cout<<'0'<<endl;
}
else if(n==1)