Fibonacci Sequence

#include <stdio.h>

int FibSeq1(int n)
{
    if(n == 0 || n == 1)
    {
        return 1;
    }

    return FibSeq1(n - 1) + FibSeq1(n - 2);
}

int FibSeq2(int n)
{
    if(n == 0 || n == 1)
    {
        return 1;
    }

    int first = 1;
    int second = 1;
    int sum = 0;

    for(int i = 2; i <= n; ++i)
    {
        sum = first + second;

        first = second;
        second = sum;
    }

    return sum;
}

int main()
{
    int ret = 0;

    ret = FibSeq2(2);
    ret = FibSeq2(3);
    ret = FibSeq2(5);
    ret = FibSeq2(8);
    ret = FibSeq2(100);

    return 0;
}