C++ Templates: Convincing self against code bloat

Question

I have heard about code bloats in context of C++ templates. I know that is not the case with modern C++ compilers. But, I want to construct an example and convince myself.

Answer 1

One test would be to put a static variable in data(), and increment it on each call, and report it.

If MyArray::data() is occupying the same code space, then you should see it report 1 and then 2.

If not, you should just see 1.

I ran it, and got 1 then 2, indicating that it was running from the same set of code. To verify this was indeed true, I created another array with size parameter of 50, and it kicked out 1.

Full code (with a couple tweaks and fixes) is below:

Array.hpp:

#ifndef ARRAY_HPP
#define ARRAY_HPP
#include 
#include 

using std::size_t;

template< typename T, size_t N >
class Array {
  public:
    T * data();
  private:
    T elems_[ N ];
};

template< typename T, size_t N >
T * Array::data() {
    static int i = 0;
    std::cout << ++i << std::endl;
    return elems_;
}

#endif

types.hpp:

#ifndef TYPES_HPP
#define TYPES_HPP

#include "Array.hpp"

typedef Array< int, 100 > MyArray;
typedef Array< int, 50 > MyArray2;

#endif

x.cpp:

#include "types.hpp"

void x()
{
    MyArray arrayX;
    arrayX.data();
}

y.cpp:

#include "types.hpp"

void y()
{
    MyArray arrayY;
    arrayY.data();
    MyArray2 arrayY2;
    arrayY2.data();
}

main.cpp:

void x();
void y();

int main()
{
    x();
    y();
    return 0;
}