C++ pointer vs reference

Hi,
I am new to C++, and I think it will take several years for me to
be profient with C++. My first struggle with C++ is pointer and
reference. Althoug I think there is no different between using pointer or reference in C++, but I think each has its own place and purpose which the author of creating this C++ language has
something intended with each type.
Do you guys, experienced programmer, help to explain me what
the difference between them. When I can use Pointer and when
I can use reference. Does it difference because pointer is more efficience in execution speed than reference.
For example below that I have learn in the book but not quite clearly understanding:

Code:

---


class A {
              public:
                  A();
                  int getnum();
            private:
                  int number;
          };

class B  {  public:    B();
                              void setData();
                private:
                  float data1;
            };

class C  {
                public:
                  C();
                  setAlldata();

              private:
                  A  *PtrToA;          //what the difference between these
                  B  &ReferenceToB;  //two? Why not use both pointers
            };

---

Your help is grateful.
C-Dumbie

Both pointers and references return an address of memory. Pointers can be repointed, references cannot. Hence, references are considered safer since you cannot return a NULL reference. There is no speed penalty for using one over the other. References have the added language facility of being manipulated with the "." operator and with the "*" dereference.
Here are two identical snippets:

Code:

---


Obj * Foo( int * i ) {
  if( *i > 0) {
    *i = 1;
  } else {
    *i = 0;
  }
 return this;
}



Obj& Foo( int& i ) {
  if( i > 0) {
    i = 1;
  } else {
    i = 0;
  }
 return *this;
}

---

Thus references have the added benefit of easier syntax.

Quote:

---

*i = 1

---

Shouldn't we use i=1?
Because in *i=1, *i means the address which i is pointing to not the content of the address i is pointing to, I'm confused so please tell me.

Quote:

---

Originally posted by ammar
Because in *i=1, *i means the address which i is pointing to not the content of the address i is pointing to, I'm confused so please tell me.

---

The opposite.
truth = inverse(your_statement);

Thanks for the clarification, I'm always confised with ponters.