Use the functions of a vector objects using a pointer

Question

1).Why did I get this error? What is the correct syntax?

2).Is there a way to write the same code without using the library "vector"?

#include <vector>

myClass()
{
    public:
        myClass(int x,int y);
        void doThis()
        {
            //Something
        }
}

int main(void)
{
    std::vector<myClass>*ex_vector = new std::vector<myClass(5,myClass{10,10});
    ex_vector[0]->doThis(); //Error Here
    delete []ex_vector;
}

I get this error:

error: base operand of '->' has non-pointer type 'std::vector<myClass>'

aschepler · Accepted Answer · 2017-04-14 12:15:07Z

5

The correct syntax is

(*ex_vector)[0].doThis();

Also, you should delete ex_vector; and not delete[] ex_vector; since the type of the new was not a raw array type.

However, there's rarely a good reason to new a std::vector. Just use a plain object.

answered Apr 14, 2017 at 12:15

aschepler

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4 Comments

nostyn Over a year ago

2).Is there a way to write the same code without using the library "vector"?

aschepler Over a year ago

Not easily, since myClass doesn't have a default constructor.

TuanDT Over a year ago

Vote up for the comment on preferring plain object over pointers. Note that if you are really desperate for pointers, use a smart pointer rather than a raw one.

nostyn Over a year ago

Wishing I can add it. The point is that I have to deallocate memory in just end up using the vector.

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