Pointer to a class with array indexing operator overload

Question

I have a class which has overloaded the array index operator[]. Now I have to create a pointer to that class, How can I use index operator [] using pointer to the class. Following code works fine, but if i un-comment the basicVector * a = new basicVector(10) line and put -> in place of ., I get errors.

Please see this link for compiler settings and code.

#include <iostream>       // std::cout
#include <queue>          // std::queue
#include <string>
#include <string.h>
#include <stdint.h>
#include <vector>

using namespace std;
class basicVector
{
private:
    uint32_t array_size;
    uint8_t * array;
public:
    basicVector(uint32_t n);
    ~basicVector();

    uint32_t size();
    uint8_t * front();
    uint8_t& operator[](uint32_t i);
};

basicVector::basicVector(uint32_t n)
{
    array_size = n;
    array = new uint8_t[n];
}

basicVector::~basicVector()
{
    delete [] array;
}

uint32_t basicVector::size()
{
    return array_size;
}

uint8_t * basicVector::front()
{
    return array;
}

uint8_t& basicVector::operator[](uint32_t i)
{
    return array[i];
}

int main ()
{   //basicVector * a = new basicVector(10);
    basicVector a(10);
    cout <<a.size()<<endl;

    for(uint8_t i=0; i < a.size(); i++)
    {   a[i] = i+50;    //how to do this correctly when "a" is pointer?
    }

    uint8_t * b = &a[3];    //how to do this correctly when "a" is pointer?
    *b = 45;

    for(uint32_t i=0; i < a.size(); i++)
    {   cout<<a[i]<<endl;   //how to do this correctly when "a" is pointer?
    }
    return 0;
}

Well, since it's a pointer you need to dereference it first. So: (*a)[i] = i+50; — DimChtz
– DimChtz, Commented May 7, 2018 at 14:18

N00byEdge · Accepted Answer · 2018-05-07 14:17:21Z

3

With the following declaration:

basicVector *a = new basicVector(10);

You could dereference the pointer (preferred):

uint8_t n = (*a)[5];

Or call the operator using the operator syntax:

uint8_t n = a->operator[](5);

answered May 7, 2018 at 14:17

N00byEdge

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