chapter21drill_vector2.cpp

// Osman Zakir
// 12 / 18 / 2017
// Bjarne Stroustrup: Programming: Principles and Practice Using C++ 2nd Edition
// Chapter 21 Drill "More vector use"
// Drill Specifications:
/**
 * 1. Read some floating-point values (at least 16 values) from a file into a
 * vector<double> called vd .
 * 2. Output vd to cout .
 * 3. Make a vector vi of type vector<int> with the same number of elements
 * as vd ; copy the elements from vd into vi .
 * 4. Output the pairs of ( vd[i] , vi[i] ) to cout , one pair per line.
 * 5. Output the sum of the elements of vd .
 * 6. Output the difference between the sum of the elements of vd and the sum
 * of the elements of vi .
 * 7. There is a standard library algorithm called reverse that takes a sequence
 * (pair of iterators) as arguments; reverse vd , and output vd to cout .
 * 8. Compute the mean value of the elements in vd ; output it.
 * 9. Make a new vector<double> called vd2 and copy all elements of vd with
 * values lower than (less than) the mean into vd2 .
 * 10. Sort vd ; output it again.
 */

#include <stdexcept>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include "../../cust_std_lib_facilities.h"

std::vector<double> fill_vector(std::istream &is);

int main()
{
	using std::vector;
	using std::string;
	using std::ifstream;
	using std::cin;
	using std::cout;

	cout << "Please enter filename: ";
	std::string filename;
	cin >> filename;
	ifstream ifs{ filename };
	vector<double> vd;
	try
	{
		if (ifs)
		{
			vd = fill_vector(ifs);
			for (const auto &d : vd)
			{
				std::cout << d << '\n';
			}
		}
		else
		{
			error("Thrown in main(), line 57: can't open file ", filename);
		}
	}
	catch (const std::runtime_error &e)
	{
		std::cerr << "Caught in main(), line 63; " << e.what() << '\n';
	}

	try
	{
		if (!vd.empty())
		{
			vector<int> vi;
			std::copy(vd.begin(), vd.end(), vi.begin());
			for (auto iter_double = vd.begin(); iter_double != vd.end(); ++iter_double)
			{
				for (auto iter_int = vi.begin(); iter_int != vi.end(); ++iter_int)
				{
					cout << '(' << *iter_double << ',' << *iter_int << ")\n";
				}
			}
		}
	}
	catch (const std::exception &e)
	{
		std::cerr << "Caught in main() on line 83: " << e.what() << '\n';
	}
	catch (...)
	{
		std::cerr << "Structured exception caught on line 87\n";
	}
	keep_window_open();
}

std::vector<double> fill_vector(std::istream &is)
{
	using std::vector;

	vector<double> vec;
	for (double val; is >> val;)
	{
		vec.push_back(val);
	}
	return vec;
}