Having a template compile for only known execution path - c++

Question

In the example below I am having a issue with getting it to compile even though I know the known execution path will be "safe". By "safe" I mean I know I will only use it in this manner. Is there an algorithm or a better way to structure a scenario where even though I know I will never have a "Type" of "float" passed with a "kind" value of 1?
The error in particular I get is that
error C2248: 'foo::foo' : cannot access private member declared in class 'foo'
Test case example
#include <vector>
using namespace std;
class foo {
private:
foo(float val) {
val = 99.0f;
}
public:
foo(int val) {
val = 2;
}
};
template<typename Type>
struct bar {
public:
vector<Type> array;
void Add(Type value) {
array.push_back(value);
}
};
class bunny {
bar<float> floats;
bar<foo> foos;
public:
template<typename Type>
void Initialize(int kind, Type value) {
if(kind == 0)
floats.Add(value);
else if(kind == 1)
foos.Add(value);
}
};
int main(void) {
bunny first; first.Initialize(0, 1.0f);
//bunny second; second.Initialize(1, 0);
return 0;
}

Answer 1

In C++ you can have multiple functions that have the same name but differ in number or type of the arguments, so, for example, you can have two functions:
void foo(float a)
{
std::cout << "Float!" << a << std::endl;
}
void foo(int a)
{
std::cout << "Int!" << a << std::endl;
}
If you call one of these functions the compiler will deduce what function to call based on the argument you gave to the function.
That is called function overloading.
In your case you could probably rewrite your bunny class to something like this:
class bunny {
bar<float> floats;
bar<foo> foos;
public:
void Initialize(foo value) {
foos.Add(value);
}
void Initialize(float value) {
floats.Add(value);
}
};
If you call first.Initialize(1.0f) the compiler knows that he needs to call void Initialize(float value) because you passed a float to the function.