C++ - Initialize array of pointers within a constructor

Question

I need an array of char * defined in as a class's attribute, and initialize it with a length inside the class's constructor. For example:

Foo.h:

class Foo{
    public:
        char * array[1]    // declare the array here, syntax unsure
        Foo(int length);
}

Foo.cpp:

Foo::Foo(int length){
    array[length]      // set the length of the array here, syntax unsure
}

Not sure about the syntax...I've only seen declaration of array of pointers with a length. I wonder how to declare it first and set/redeclare a new length later.

Answer 1

How to use a dynamic array

Use an std::vector :

class Foo{
public:
    std::vector<char*> array;
    Foo(int length) : array(length) {}
}

In:

array(length) 

you will construct a container with length default constructed char* . You can even use one of the other useful constructors. Specifically if you want to define length copies of the element x you can use:

array(length, x)

You can then, eventually, push them in with push_back / emplace_back .

Few minor touches

If char* is semantically a string, then you should use std::vector<std::string> .

And if the class is minimal as you described it, then you can simply use:

using Foo = std::vector<std::string>;

The type alias won't create a new type, it will only create a new type alias .