C pointers, arithmetic, & types

pointer_arith_types.c

#include <stdio.h>
#include <stdlib.h>

int main() {
  char* c = malloc(10);
  int* i = malloc(10);

  // Print the size of a char and int type.
  printf("Size of char is %lu.\n", sizeof(char));
  printf("Size of int is %lu.\n", sizeof(int));


  // Print the address of c and i.
  printf("Address of c is %p.\n", c);
  printf("Address of i is %p.\n", i);

  // Print the address of c+1 and i+1.
  printf("Address of c+1 is %p.\n", c+1);
  printf("Address of i+1 is %p.\n", i+1);

  // Convert the addresses to long in order to show the difference.
  // Note: if you don't do this, the difference will be 1 since the
  //       compiler will take the type under consideration.
  long pc_value = (long) c;
  long pc_value_inc = (long) (c + 1);
  long pi_value = (long) i;
  long pi_value_inc = (long) (i + 1);

  // Print the difference between the addresses.
  printf("The c pointer is incremented by %ld.\n", pc_value_inc - pc_value);
  printf("The i pointer is incremented by %ld.\n", pi_value_inc - pi_value);
}