Dynamic Memory Allocation

Pointers have no space allocated to them upon creation

The functions following functions can be used to dynamically manage memory

`void *malloc (size_t size)`	Allocates `size` bytes and returns a pointer to it
`void *calloc (size_t n_elem, size_t size)`	Allocates memory for an array of `n_elem` elements of `size` bytes each and returns a pointer to the allocated memory. The memory is initialized to zero.
`void free (void *ptr)`	Frees previously allocated memory

Example:

     
     #include <stdio.h>
     #include <stdlib.h>
     
     #define NUM     10
     
     int main ( void ) {
       int *ptr,
           *ptr_inc;
     
       /*
        * allocate NUM integers
        */
       if ( NULL == ( ptr = calloc ( NUM, sizeof ( int ) ) ) ) {
         printf ( "Unable to allocate memory.  Exiting...\n" );
         return ( 1 );
       }
     
       /* set the values */
       for ( ptr_inc = ptr; ptr_inc < ( ptr + NUM ); ptr_inc++ )
         *ptr_inc = ptr_inc - ptr;    
         
       /* print the values */
       for ( ptr_inc = ptr; ptr_inc < ( ptr + NUM ); ptr_inc++ )
         printf ( "%d\n", *ptr_inc );
     
       /* free the memory */
       free ( ptr );
     
       return ( 0 );
     }

Output: