Also the article little bit explains about forward declaration, which prevents from recompiling.

Solution is easy, as follows:

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

int main(int argc, char** argv){
	int a[]={2,6,15,21,34};  //simple test array
	int n=sizeof(a)/sizeof(int);

	int m=0;
	for_each(a,a+n,[&m](int x){ m+=x;});

	int* M=new int[m+1];
	for(int i=0;i<=m;i++){
		M[i]=0;
	}
	M[0]=1;

	for(int i=0;i<n;i++){
		for(int j=m;j>=a[i];j--){
			M[j]|=M[j-a[i]];
		}
	}
	int k=55; //simple test num

	cout<<"Sum to "<<k<<" is "<<(M[k]?" possible":" not possible")<<endl;
}

#define x(i) x##i

When x(1) is invoked it becomes x1, since ## appends, while # gives arguments.

A header file should be included only when a forward declaration would not do the job.
a.The size of the class’ objects is not needed.
b.The names or types of any of the class’ members are not needed.
c.The prototypes to or names of any of the class’ member functions are not needed
The header file should be so designed that the order of header file inclusion is not important.
The header file inclusion mechanism should be tolerant to duplicate header file inclusions.

        vector<int> values(10);
	int i = 0;
	generate(values.begin(), values.end(), [&]{return ++i;} );

	// 1. Calculate the sum of the elements of the vector in parallel.
	combinable<int> sums;
	parallel_for_each(values.begin(),values.end(), [&](int n)
	{
		sums.local() += n;}
	);

	// 2. Combine/Reduce into final result
	int result = sums.combine([](int left, int right) { return left + right; });

#define NULL 0
//or sometimes
#define NULL (void *)0

This is explained at http://channel9.msdn.com/shows/Going+Deep/Stephan-T-Lavavej-Everything-you-ever-wanted-to-know-about-nullptr/

#include<iostream>
#include <conio.h>
#include <ppl.h>
#include <windows.h>
#include <vector>
#include <algorithm>
using namespace std;
using namespace Concurrency;

__int64 GetTime(){
	return GetTickCount();
}

void makeDouble(vector<int> vec){
	for_each(vec.begin(),vec.end(),[&](int i){
		cout<<2*i<<" ";
	});
	cout<<endl<<endl<<endl<<endl;
}

void parallel_makeDouble(vector<int> vec){
	parallel_for_each(vec.begin(),vec.end(),[=](int i){
		cout<<2*i<<" ";
	});
	cout<<endl<<endl<<endl<<endl;
}

int main(int argc, char** argv){
	vector<int> v(200);
	int n=0;
	generate(v.begin(),v.end(),[&](){ return n++;});

	__int64 begin=GetTime();
	makeDouble(v);
	__int64 end=GetTime();
	cout<<"Seq:"<<end-begin<<endl;

	begin=GetTime();
	parallel_makeDouble(v);
	end=GetTime();
	cout<<"Parallel:"<<end-begin<<endl;
	getch();
	return 0;
}

#include<iostream>
#include <conio.h>
#include <ppl.h>
using namespace std;
using namespace Concurrency;

void makeDouble(int n){
	for(int i=0;i<n;i++){
		cout<<2*i<<" ";
	}
	cout<<endl<<endl<<endl<<endl;
}

void parallel_makeDouble(int n){
	parallel_for(0,n,[](int i){
		cout<<2*i<<" ";
	});

}

int main(int argc, char** argv){
	makeDouble(100);
	parallel_makeDouble(100);
	getch();
	return 0;
}

Output:

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 5
6 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 102 104 106
108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140 142 144 146
148 150 152 154 156 158 160 162 164 166 168 170 172 174 176 178 180 182 184 186
188 190 192 194 196 198

50 0 150 100 52 54 56 58 60 176 178 180 182 184 186 188 190 192 194 196 198 62 1
02 104 152 154 156 164 166 168 1702 64 66 68 70 72 172 174 158 106 108 110 112
114 116 118 120 162 4 122 124 126 128 130 132 134 136 138 140 28 74 76 78 80 82
84 86 88 90 92 94 96 98 30 32 34 36 38 40 42 44 46 48 142 6 144 160 146 8 10 12
18 20 148 22 14 24 16 26

http://www.youtube.com/user/GoogleTechTalks#p/u/6/hFSPHfZQpIQ