How do i completely erase an array and replace it with a vector?

Question

I've been working on this assignment for my class for about a day and I've completed just about everything. The only thing I'm missing is removing my array and replacing it with a vector.

#ifndef MENU
#define MENU
#include <vector>
const int MAXCOUNT = 20;
struct menuItem
{
    void(*func)();
    char decript[50];
};
class Menu
{
private:
    //vector <int> v;       i tried replacing the "mi"'s in the menu.cpp file with v.push_back but i kept getting pointer errors      
    menuItem mi[MAXCOUNT];      
    int count = 0;              
    void runSelection();
public:
    Menu();
    void addMenu(char *Description, void(*f)());
    void runMenu();
    void waitKey();
};
#endif

This is the cpp file. Im trying to replace the array mi with v. I know im missing something but I can't figure it out so I'm just posting it working with an array.

 Menu::Menu()
    :count(0)
{

}
void Menu::addMenu(char *Description, void(*f)())
{
    if (count < MAXCOUNT)
    {
        this->mi[count].func = f;
        strcpy(this->mi[count].decript, Description);
        count++;
    }
}
void Menu::runMenu()
{

    for (;;)
    {
        system("CLS");
        for (int i = 0; i < count; i++)
        {
            cout << this->mi[i].decript << endl;

        }
        runSelection();
    }
}
void Menu::waitKey()
{
    cout << "Press any key to continue" << endl;
    while (!_kbhit());
    fflush(stdin);
}
void Menu::runSelection()
{
    int select;
    cin >> select;
    if (select <= count)
        this->mi[select - 1].func();

}

Why are you replacing an array of `menuItem` with a vector of `int`? — Barmar, Sep 19 '16 at 22:00
brain fart, this was my first experience with vectors and I assumed it was used like this. — dnun99, Sep 19 '16 at 22:03

πάντα ῥεῖ · Accepted Answer · 2016-09-19T22:01:11.537

1

The simplest way should be to replace

    menuItem mi[MAXCOUNT];

with

   std::vector<menuItem> mi;

and initialize it in your constructor properly

Menu::Menu()
    :count(0)
    ,mi(MAXCOUNT)
{

}

Supposed you had working code before, this should replace the raw array seamlessly.

With the current c++ standard you can even simply use

   std::array<menuItem,MAXCOUNT> mi;

this wouldn't even require initialization in the constructor.

edited Sep 19 '16 at 22:01

answered Sep 19 '16 at 21:44

πάντα ῥεῖ

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it worked perfectly. Wow you can use the struct as a type in the vector? – dnun99 Sep 19 '16 at 21:56
and in the my functions I dont have to use .push_back at all? – dnun99 Sep 19 '16 at 21:57
this 100% kills the array in my project? That's awesome. – dnun99 Sep 19 '16 at 21:57
@dnun99 I'll give you even another option. – πάντα ῥεῖ Sep 19 '16 at 22:01
did u type array on purpose? if so you can include the size in this way? – dnun99 Sep 19 '16 at 22:05
@dnun99 Yes, of course. It's different from `std::vector`, see [`std::array`](http://en.cppreference.com/w/cpp/container/array) please. – πάντα ῥεῖ Sep 19 '16 at 22:07
are these new? my professor is kinda old school and ive never seen something like this. do u recommend any books with modern programming? – dnun99 Sep 19 '16 at 22:10
@dnun99 http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list – πάντα ῥεῖ Sep 19 '16 at 22:11
1

@dnun99 Most professors are quite old school, I'm old school as well but the difference may be I'm using the language in industry and not at university. – πάντα ῥεῖ Sep 19 '16 at 22:12
Yea I suppose fundamentals are more important in academics. Thank you for all your help. – dnun99 Sep 19 '16 at 22:14

How do i completely erase an array and replace it with a vector?

1 Answers1