Allocating array of objects inside another class (C++)

Question

How can I allocate an array of object inside another class in it's constructor?

class BloomFilter
{
public:
    BloomFilter(double fp, size_t capacity);
private:
    size_t bf_m;
    size_t bf_k;
};

class RSig {
public:
    RSig(int32_t sizeL1, int32_t sizeL2, double bfFpRate) :
        numSlot_sig(sizeL1), numSlot_bf(sizeL2)
    {
        TL_sigMem = new BloomFilter(bfFpRate, numSlot_bf)[sizeL1];
    }

private:
    int32_t numSlot_sig, numSlot_bf;
    BloomFilter* TL_sigMem;
};

The code above gives me the following error:

In constructor 'RSig::RSig(int32_t, int32_t, double)’:
error: expected ‘;’ before ‘[’ token
         TL_sigMem = new TL_sigMem(bfFpRate, numSlot_bf)[sizeL1];

Preferably, I don't want to use std::vector .

Answer 1

Like this:

#include <vector>

class RSig
{
public:
    RSig(double rate, std::size_t len) : TL_sigMen(len, BloomFilter(rate)) {}

private:
    std::vector<BloomFilter> TL_sigMem;
};

Answer 2

To create an array of objects, the syntax goes like this:

T* t = new T[<size>];

Where T is the type, t is the name of the array, and <size> is the size of the array. Now, in your situation, you would like to do this:

TL_sigMem = new BloomFilter[sizeL1];

This will create an array of BloomFilter s of size sizeL1 . However, since your BloomFilter does not seem to have a default constructor, you'll need to either use std::vector and its emplace_back() function, whip out your own (rather complicated) approach, or to create an array of pointers instead:

BloomFilter** TL_sigMem;

TL_sigMem = new BloomFilter*[sizeL1];

TL_sigMem[0] = new BloomFilter(...);