Ranged based for loop not compiling with vector of abstract class

Asked Jul 08 '16 at 13:45

Active Jul 08 '16 at 13:48

Viewed 40 times

I have this piece of code:

#include <iostream>
#include <string>
#include <vector>

class MyAbstract
{
    public:
    std::string id;

    virtual void doStuff() = 0;
    virtual ~MyAbstract() {}
};

int main()
{
    std::vector<MyAbstract> myList;

    for(auto item : myList)
    {
        //DoSomething
    }
}

But it doesn't compile with this error:

error: cannot allocate an object of abstract type 'MyAbstract'

Visual Studio 2015 Error:

cannot instantiate abstract class

Here is the code online: http://cpp.sh/3etnq

What am I missing here?! This works:

for (auto it = myList.begin(); it != myList.end();)

edited Jul 08 '16 at 13:47

asked Jul 08 '16 at 13:45

DoubleVoid

4

"Fixing" the loop won't fix the fundamental problem:a vector of an abstract type is useless because you won't be able to store anything in it. – juanchopanza Jul 08 '16 at 13:47
Let's assume I used a vector of pointers :) – DoubleVoid Jul 08 '16 at 13:50
2

If you are using vector of pointer, then you won't have this problem. – Revolver_Ocelot Jul 08 '16 at 13:51
I'm guessing you want `for (auto& item : myList)` - won't solve the abstract class problem, but will prevent the copy. – Jesper Juhl Jul 08 '16 at 13:53
You're right, guess I have to think a little bit more about my design here then ... thanks for your answers! – DoubleVoid Jul 08 '16 at 13:54
http://ideone.com/ZrWjSH – Pixelchemist Jul 08 '16 at 13:57
Thanks, Pixelchemist! – DoubleVoid Jul 08 '16 at 13:59

Ranged based for loop not compiling with vector of abstract class

0 Answers0