Difference between macro and pass by reference?

Like the title says, what is the difference between using a macro, which just textually substitutes whatever, as opposed to just writing a function with reference parameters? I know there must be a difference, or else there would be no need for macros. Can someone please help me to understand the difference, possibly with an example? ;) TIA.

Macros shouldn't be used as functions - it's a C-style to make something inline. It's a bit harder to debug and off use due the inlines in C++.

Code:

---

Macro
#define foo(x) x+  // see the error
...
int main()
{
  int y;
  foo(y);  // This is the line you get the error
  char s[] = "Hello world";
  foo(s);  // Want to know what happens?
  ...


inline
inline void foo(const int &x)
{
  x+;  //  Now you'll get the error here
}

int main()
{
  int x;
  foo(x);
  char s[] ="dlrow olleH";
  foo(s);  //  And another one here
  ...

---

Inline functions also enforce type safety.........

Also #defines may never actually reach the compiler as they are converted by the preprocessor beofre compilation.....I have read of occasions where this can give problems debugging....