// header files
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

// local constants

/*
Name: Fibonacci Sequence
Process: Accepts single integer, prints out up to nth term of the sequence.
Function input/parameters: argc and argv command line arguments
Function output/parameters: NONE
Function output/returned: NONE
Device input/---: NONE
Device output/---: NONE
Dependencies: included by standard libraries
*/
int main(int argc, char *argv[])
{
    // define local variables
    int fibonacciNumber = 0;
    int prevFibonacciNumber, prevPrevFibonacciNumber;
    int fibN1 = 0, fibN2 = 1;
    int nthTerm = atoi(argv[1]);
    int counter;
    // do calculations
    if(argc == 2 && nthTerm >= 0)
    {
        // check to see if the correct number of arguments are included
        // fibonacci sequence loop until n.
        fibonacciNumber = fibN1 + fibN2;
        prevFibonacciNumber = fibonacciNumber;
        fibonacciNumber = fibN2 + prevFibonacciNumber;
        prevPrevFibonacciNumber = prevFibonacciNumber;
        prevFibonacciNumber = fibonacciNumber;
        for(counter = 0; counter < nthTerm - 2; counter++)
        {
            // get the next fibonacci number
            fibonacciNumber = prevPrevFibonacciNumber + prevFibonacciNumber;
            prevPrevFibonacciNumber = prevFibonacciNumber;
            prevFibonacciNumber = fibonacciNumber; 
        }
        printf("The %dth term of the Fibonacci Sequence is: %d\n", nthTerm, prevPrevFibonacciNumber);
    }
    else
    {
        // fail program
        printf("Please provide one integer greater than zero.\n");
        return -1;
    }
    // display results
    // done in do calculations
    // return success
    return 0;
}