Writing an allocator

[Protoman]

Why won't the compiler let me write:

#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;

template <class T>
class Allocator
{
public:
Allocator(){}
T* allocate(){static long long i=0; T* j=new(pool) T; i++; return
&*j;}
private:
static T pool[1000000];
};

int main()
{
Allocator<long long> alloc;
long long* i=alloc.allocate();
system("PAUSE");
return 0;
}

Any suggestions? Thanks.

 

[Neelesh Bodas]

Why won't the compiler let me write:

#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;

template <class T>
class Allocator
{
public:
Allocator(){}
T* allocate(){static long long i=0; T* j=new(pool) T; i++; return
&*j;}

the argument to placement new is a memory location (void*) . long long
int cannot be converted to void*. Hence this will not compile. Use
&pool instead.

private:
static T pool[1000000];
};

You need to define the static memeber "pool" outside the class:

int main()
{
Allocator<long long> alloc;
long long* i=alloc.allocate();
system("PAUSE");
return 0;
}

Any suggestions? Thanks.

With these two changes it worked in my case.

 

[Old Wolf]

Why won't the compiler let me write:

#include <iostream>
#include <cstdlib>
#include <new>
using namespace std;

template <class T>
class Allocator
{
public:
Allocator(){}
T* allocate(){static long long i=0; T* j=new(pool) T;
i++; return &*j;}

C++ does not have "long long".

 

[Pete Becker]

C++ does not have "long long".

It does, as of last month. Many compilers already support it.