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Are all pointers evil? Well, they make your software more flexible and dynamic. Moreover, they are necessary in C to implement reference parameters.

Parameters are always passed by value in C. If you want to return multiple values by a function, you need reference parameters. C programmers use an idiom for reference parameters by using pointers:

  // a and b are reference parameters
  void f (int *a, int *b) {
    *a = 1; *b = 2; // return values
  }

  ...f (&x, &y)... // pass by reference

In contrast, the following code creates a dangling reference:

  int *p;

  void f (int *a) {
    p = a; 
  }

  void g() {
   int x;
   f (&x);
  }

  int main () {
   g ();
   ...*p... // ouch, a dangling reference
  }