#include <stdio.h>
#include <ctype.h>

int globalInt = 10000;

// ALL values are passed by value in C.

// when you see a pointer parameter, you don't know if
// what the code's author intends.  Could be they intend
// the method to return a value in the memory pointed at
// by the pointer (which is call-by-reference-like).
// Could be they want to provide access to something large,
// like a structure, without the cost of copying it to  the stack.
// Could be an array, which can't be passed by value.

void sub(int x, int *intPtr, int *kindaRef) {
  x = 0;                        // this is an assignment to a local variable
  intPtr = &globalInt;   // this is an assignment to a local variable
  *kindaRef = 0;          // this uses a local variable to access (shared) memory
}

int main(int argc, char *argv[]) {

  int localInt = 1;
  int refInt = 100;
  int *pInt = &localInt;

  printf("localInt / pInt / refInt => %d / %p (%d) / %d\n",
	 localInt, pInt, *pInt, refInt);

  sub(localInt, pInt, &refInt);

  // Note that pint didn't change!
  printf("localInt / pInt / refInt => %d / %p (%d) / %d\n",
	 localInt, pInt, *pInt, refInt);

  return 0;
}