custom vector class

so i want to make my own vector class with functions that i use regularly like writing the array, inserting an element, sorting .. that sort of stuff.

and i was thinking i would have a public variable a[NMAX] that would be the array itself. I thought of passing the array`s length as a parameter for the constructor but I don't think i`m doing it right.

main

#include <iostream>
#include <vector.h>

using namespace std;

int main()
{
    vector v(10);

    for (int i=0; i<10; i++)
        cout << v.a[i] << " ";

    return 0;
}

vector.h

#ifndef VECTOR_H
#define VECTOR_H


class vector
{
    public:
        vector(int n);
        virtual ~vector();
        int NMAX;
        int a[NMAX];
    protected:
    private:
};

#endif // VECTOR_H

vector.cpp

#include "vector.h"
#include <iostream>

using namespace std;

vector::vector(int n)
{
    //ctor

    NMAX = n;

}

vector::~vector()
{
    //dtor
}

The error I get is : invalid use of non-static data member vector::NMAX.

Do I need some pointers to get the job done ? Please help me out :)

Bazzy (6281)

You can't declare an array with a variable as size, you'll need to allocate your array on the free store
http://www.cplusplus.com/doc/tutorial/dynamic/

olly2204 (9)

thanks, that worked :D

how do i add more elements ?

Bazzy (6281)

allocate a new array, copy each element from the old to the new array, free the old array

olly2204 (9)

brilliant . thanks :)

Kyon (912)

Brilliant, yet horribly slow. I recommend using a regular vector for things like this (general purpose usage).

m4ster r0shi (2201)

Kyon wrote:
Brilliant, yet horribly slow. I recommend using a regular vector for things like this (general purpose usage).

And how do you think a regular vector does the resizing?

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custom vector class