#include <iostream>
#include <vector>
#include <stdexcept>
#include <fstream>
#include <string>
#include <stdlib.h>

using namespace std;

const string file_name = "data.txt";

void read_scores(vector<int>& scores) throw (invalid_argument)
{
	ifstream data_file;
	int temp;

	data_file.open(file_name.c_str());

	if(data_file.fail()) 
		throw invalid_argument("no file exists " + file_name);

	while(data_file >> temp)
		scores.push_back(temp);

	data_file.close();
}

double find_average(const int sum, const int divisor) throw (runtime_error)
{	
	if(!divisor) 
		throw runtime_error("divisor is zero");
	return (sum / (double) divisor); 
}

void throwing_ftn() throw (runtime_error) {
	throw runtime_error("something went wrong\n");
}

void memory_leak() throw (runtime_error) {
	string* s = new string("hello");
	
	throwing_ftn();

	delete s;
}

void no_memory_leak() throw (runtime_error) {
	string* s = new string("hello");
	
	try {
		throwing_ftn();
	} catch (...) {
		delete s;
		throw;
	}
	delete s;
}


int main() {
	vector<int> scores;
	int sum = 0;

	try {
		read_scores(scores);
		for(int i = 0; i < scores.size(); ++i) {
			sum += scores[i];
		}
		cout << "avg = " << find_average(sum, scores.size()) << "\n";
	} catch (const invalid_argument& iae) {
		cout << "unable to read data: " << iae.what() << "\n";
		exit(1);
	} catch (const runtime_error& rte) {
		cout << "unable to compute average: " << rte.what() << "\n";
		exit(1);
	}
	
	for(int i = 0; i < scores.size(); ++i) 
		cout << "score " << i << " = " << scores[i]	<< "\n";

	return 0;
}