C++ Allocate Vector Size in class variable without default initialization

Question

So I have a class (HostObject) that has a vector of complex classes (object1) inside it. Such as the pseudocode depicted below

#DEFINE ARRAY_SIZE 10
class HostOb         


        

Answer 1

You could do this by calling reserve() in default constructor.

#DEFINE ARRAY_SIZE 10
class HostObject {
  //other member variables
  vector vec; //vec(ARRAY_SIZE);  // not here

  //default constructor
  HostObject() {
    //leave vector default constructed
    vec.reserve(ARRAY_SIZE);               // but here
  }

  //my custom constructor                  // no need to change, since push_back will increase size automatically
  HostObject(double parmeter1, double parameter2, doubleparameter3) {

    //some code doing some calculations 

    for (int i = 0; i 

Also consider using static unsigned array_size = 10; as a member of class HostObject, so that you can change the size dynamically every time creating an object of HostObject.

HostObject ho1;  // array size is 10
HostObject::array_size = 20;
HostObject ho2;  // array size is 20