#include <iostream>
#include <cmath>
using namespace std;

int main()
{
 // create an array of 16 integers
 int numbers[16];

 double grades[10];   // an array of 10 doubles
 string names[100];   // array of string elements

 // use [] to access array elements
 numbers[0] = 12;
 numbers[1] = numbers[0] + 15;
 numbers[0] += 5;

 cout << numbers[0] << " and " << numbers[1] << endl;

 // how about uninitialized elements?
//  cout << numbers[2] << " and " << numbers[3] << endl;

 // typically we initialize all values
 //   using a for loop
 for ( int i = 0 ; i < 16 ; i++ )
 {
   numbers[i] = 0;
 }

 // how can we set the numbers array to
 //   be powers of two?
 //
 //                 0
 //   numbers[0] = 2  = 1
 //
 //                 1
 //   numbers[1] = 2  = 2
 //
 //                 2
 //   numbers[2] = 2  = 4
 //
 //         etc.
 for ( int i = 0 ; i < 16 ; i++ )
 {
   numbers[i] = pow( 2.0, i );
 }

 // display all values in the array:
 for ( int i = 0 ; i < 16 ; i++ )
 {
   cout << numbers[i] << endl;
 }

 // Fibonacci sequence:
 //   f[0] = 0
 //   f[1] = 1
 //   f[n] = f[n-1] + f[n-2];

 // Create an array to hold the first 20 Fibonacci numbers
 // Use a for loop to initialize the array
 int fib[20];

 // initialize the values:
 fib[0] = 0;
 fib[1] = 1;
 for ( int i = 2 ; i < 20 ; i++ )
 {
   fib[i] = fib[i-1] + fib[i-2];
 }

 // Print out the 20th Fibonacci number:
 cout << "The 20th Fibonacci number is: " << fib[19] << endl;



 return 0;
}