linq_test.cpp

#include <iostream>
#include <vector>
#include <list>
#include <string>
#include <sstream>
#include <algorithm>
#include <iterator>
#include <typeinfo>
#include "linq.hpp"

//print functions
template<typename T>
std::ostream & operator<<(std::ostream & out, const std::vector<T> & data)
{
	std::copy(data.begin(), data.end(), std::ostream_iterator<T>(out));
	return out;
}
template<typename T>
std::ostream & operator<<(std::ostream & out, const std::list<T> & data)
{
	std::copy(data.begin(), data.end(), std::ostream_iterator<T>(out, "  "));
	return out;
}

struct person
{
	int age;
	std::string name;
	friend std::ostream& operator << (std::ostream & out, const person & p)
	{
		return out << "("<<p.age<<","<<p.name<<")" << std::endl;
	}
};

int main() 
{

        using namespace linq;

	//create a vector of persons and print them
	std::vector<person> persons = { 
		 {1, "Aleeza"}, {3, "Nayab"}, {13, "Ashraf"}, {16, "Adil"}, 
		 {20, "Ahsan"}, {21, "Zartab"}, {17, "Nadim"}, {19, "Nafis"}, 
		 {13, "Neha"}, {15, "Zeeshan" }, {11, "Farah"}, {13, "Fauzia"},
		 {23, "Nilufer"}, {24, "Talat"}, {7, "Tufail"}, {8, "Sana"} 
	};
	std::cout << "\tOriginal\n" << persons << std::endl;

	//orderby age and print the result 
	auto v1 = persons | orderby([](const person & p) { return p.age; });
	std::cout << "\tOrder by Age\n" << v1 << std::endl;

	//filter all teenagers then orderby name, and print the result
	auto v2 = persons 
		| where([](const person & p) { return p.age >=13 && p.age <= 19 ; }) 
		| orderby([](const person & p) { return p.age; });
	std::cout << "\tFilter Teenagers, and Order by Age\n" << v2 << std::endl;

	//filter all teenagers then orderby name, and print the result
	auto v3 = persons 
		| where([](const person & p) { return p.age >=13 && p.age <= 19 ; }) 
		| orderby([](const person & p) { return p.name; });
	std::cout << "\tFilter Teenagers, and Order by Name\n" << v3 << std::endl;

	//groupby kids, teenagers, adults and print the result
	auto groups = persons | groupby([](const person & p) 
	{  
		if ( p.age < 13 ) return "Kids";
		else if ( p.age < 20 ) return "Teenagers";
		else return "Adults";
	});
	std::cout << "\tGroupby Maturity" << std::endl;
	//Note that the type of groups is std::map!
	for(auto i = groups.begin(); i != groups.end(); i++ )
	{
		std::cout << i->first << std::endl;
		std::cout << i->second << std::endl;
	}
}