Question

I have two alternatives:

class X{
int* x;
int size = ...;
void create() { 
    x = new int[size];
    use();
    delete [] x;
}
void use() {//use array}
};

or:

class X{
int size = ...;
void create(){ 
    int x[size];
    use(x);
}
void use(int arg[]) {//use arg}
}; 

which is better?

Answer 1

Option 3 is better, using std::vector.

class X{
    std::vector<int> x;
    int size; // = ...; <-- the "=" part is illegal in C++03
    void create() { 
        x.resize(size);
        use();
    } 
};

Also, your second snippet is illegal, C++ doesn’t support VLAs.