//************************************************************************************
// Problem statement: This C++ program serves as a simple Web search engine
// by computing the similarity of a query against three Web pages (documents)
// and outputting the number of the most relevant Web page.
//
// Main algorithm: do for each of the three documents
//                    1. multiply the query terms with the document terms
//		      2. multiply the document terms with the document terms
//		      3. multiply the query terms with the query terms
//                    4. sum the numbers in 1 (compute the numerator)
//                    5. sum the numbers in 2 (start to compute left term in denominator)
//                    6. sum the numbers in 3 (start to compute right term in denominator)
//                    7. multiply the square roots of the numbers in 5 and 6 (compute demoninator)
//                    8. compute the similarity measure find and output the number of the most relevant document
//
// Major variables:   d1 - 1D array for the 1st document
//                    d2 - 1D array for the 2nd document
//                    d3 - 1D array for the 3rd document
//		      q  - 1D array for the query
//		      simd1q - the similarity between d1 and q
//		      simd2q - the similarity between d2 and q
//		      simd3q - the similarity between d3 and q
//
// Program limitations: hardcoded for 3 documents, 1 query, and 7 terms (keywords);
//		        does not rank documents (only outputs most relevant document).
//
//*********************************************************************************

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

int main()
{

	double d1[7] = {0,0,1,0.4,0,0.2,0.4}; // document 1
	double d2[7] = {1,0.25,0.25,0,0,0,0}; // document 2
	double d3[7] = {0,0.43,0,0,0.57,0.29,1}; // document 3

	double q[7] = {0,0.2,0.6,0,0.2,0.3,0}; // the query

	double dTermsqTerms = 0.0;
	double dTermsSquared = 0.0;
	double qTermsSquared = 0.0;

	double document =0.0;
	double query = 0.0;

	double numerator =0.0;
	double denominator = 0.0;

	double simd1q, simd2q, simd3q = 0.0;

	// compute the similarity function in stages for the 1st document
	for(int i=0; i<7; i++)
	{

		// multiply the appropriate terms
		dTermsqTerms = d1[i] * q[i];
		dTermsSquared = d1[i] * d1[i];
		qTermsSquared = q[i] * q[i];

		// sum them up accordingly

		numerator = numerator + dTermsqTerms;

		document = document + dTermsSquared;
		query = query + qTermsSquared;
	}


	// add code to compute the denominator for the 1st document

	denominator = sqrt( numerator) * sqrt(query);

	cout << "The denominator for the 1st document is " << denominator;

	// add code to compute the similarity for the 1st document

	simd1q = numerator / denominator;

    // add code to output the similarity for the 1st document

	cout << endl << "The similarity for the 1st document is: " << simd1q;

	// add code to initialize the variables for the 2nd document

	denominator = 0;
	numerator = 0;
	query = 0;
	document = 0;

	// add code to compute the similarity function in stages for the 2nd document

	for(int i=0; i<7; i++)
	{

		// multiply the appropriate terms
		dTermsqTerms = d2[i] * q[i];
		dTermsSquared = d2[i] * d2[i];
		qTermsSquared = q[i] * q[i];

		// sum them up accordingly

		numerator = numerator + dTermsqTerms;

		document = document + dTermsSquared;
		query = query + qTermsSquared;
	}

	denominator = sqrt( numerator) * sqrt(query);

	cout << endl << "The denominator for the 2nd document is " << denominator;


	simd2q = numerator / denominator;

	cout << endl << "The similarity for the 2nd document is: " << simd2q;


    // add code to initialize the variables for the 3rd document

	denominator = 0;
	numerator = 0;
	query = 0;
	document = 0;

	// add code to compute the similarity function in stages for the 3rd document

	for(int i=0; i<7; i++)
	{

		// multiply the appropriate terms
		dTermsqTerms = d3[i] * q[i];
		dTermsSquared = d3[i] * d3[i];
		qTermsSquared = q[i] * q[i];

		// sum them up accordingly

		numerator = numerator + dTermsqTerms;

		document = document + dTermsSquared;
		query = query + qTermsSquared;
	}

	denominator = sqrt( numerator) * sqrt(query);

	cout << endl << "The denominator for the 3rd document is " << denominator;

	simd3q = numerator / denominator;

	cout << endl << "The similarity for the 3rd document is: " << simd3q;



	// add code to find and output the most relevant document