Fibonacci使用递归和循环实现

#include<stdio.h>

double Fibonacci(int i);
double Fibonacci_(int i);

int main(void)
{
    int i;
    printf("Enter the number i:
");
    scanf("%d", &i);

    printf("%f  %f",Fibonacci(i),Fibonacci_(i));
    return 0;
}
double Fibonacci(int i)
{
    double k=1;
    double g;
    for(double n=0;i-1>=0;i--)
    {
        g=k+n;
        n=k;
        k=g;
    }
    return g;
}
double Fibonacci_(int i)
{
    double k;
    if(i==2) return 2;
    else if(i==1) return 1;
    else if(i<=0) return 0;
    else
        k=Fibonacci_(i-1)+Fibonacci_(i-2);
    return k;
}