#include <iostream>
#include <fstream>
#include <string>
using namespace std;

//////////////////////////////////////////////////////
//Prototypes for readDoubles and dotProduct goes here.
//////////////////////////////////////////////////////
double*  readDoubles (string, int&);
double dotProduct(double*, double*, int);

int main()
{
     int size1, size2;

     //read in the two vectors
     double* v1 = readDoubles("hw25_vector1.txt", size1);
     cout << "Read vector 1.  Size is:  " << size1 << endl;
     double* v2 = readDoubles("hw25_vector2.txt", size2);
     cout << "Read vector 2.  Size is:  " << size1 << endl;

     //calculate dot product
     double dp = dotProduct(v1, v2, size1);

     //Output the result
     cout << "The dot product of Vector1 and Vector2 is: " << dp << endl;

     return 0;
}
//////////////////////////////////////////////////////
//Definitons for readDoubles and dotProduct goes here.
//////////////////////////////////////////////////////

double*  readDoubles (string filename, int& size)
{
		// open file 
		ifstream fin(filename.c_str());

		// get size from the file
		fin >> size;

		//  make the array
		double *vec;
		vec = new double[size];

		// fill in array from the file
		for (int i=0; i<size; i++)
		{
			fin >> vec[i];
		}

		return vec;
}





// Compute dotproduct of vec1 and vec2, each of size 'size'
double  dotProduct (double *vec1, double *vec2, int size)
{
    double result = 0;
    for (int i=0; i<size; i++)
    {
        result = result + vec1[i] * vec2[i];
    }
    return result;
}