Difference between & and * as a parameter

Question

What is the difference between the following two parameter types? The first accepts a pointer, which is in effect a memory address, and the second is also a memory address?

foo(float& bar)
{
    // do stuff
}

foo(float* bar)
{
    // do stuff
}

Could you not call both with:

float pow = 3.0f;

foo(&pow);

or

float* pow = 3.0f;

foo(pow);

Answer 1

• A pointer can be NULL, while a reference can't. This can be useful if you need to pass a NULL object for whatever reason.

• With the pointer syntax, you pass a pointer when you call the function. With references, you just pass the variable:

  refer(float& bar) {}
  point(float* bar) {}
  
  float afloat = 1.0f;
  
  refer(afloat);
  point(&afloat);
  

  This means with the pointer syntax you have to pass a pointer when you call the function. With the reference syntax, you don't know if the function takes it by reference or by value without looking at the function definition.

• With the reference syntax you don't have to dereference the pointer in your function, and work with it more naturally in your // do stuff section.

  foo(float& bar)
  {
      bar = 3.0f;
  } 
  
  // versus
  
  foo(float* bar)
  {
      *bar = 3.0f;
  }