/*
 * SelfTest.question3.c
 * Chapter 11
 * By: John Stile
 * Purpose: Write a function named copystr that receives two pointers to arrays 
 *          of strings with the same size.
 *          The first pointer str1 points to a string which has contents,
 *          but str2 points to a blank array.
 */
#include <stdio.h>

void copystr(char *, char * ); //prototype: takes 2 char pointers, returns nothing

int main(void) // header for main: takes nothing, returns int
{
  // Setup the 2 arrays of equal size.
  // First array has content, second is empty
  char aa[]={"His name was John"}; // declare char array and initialize

  // First method
  // char bb[ sizeof(aa) ]={}; 


  char bb[ sizeof(aa)/sizeof(aa[0]) ]={}; // declare char array of equal size, and initialize empty
                                          // without {}, initial print shows junk in the array.   

  char *paa, *pbb ;     // declare 2 char pointers

  paa=aa;    // initialize char pointer to &aa[0], using shorthand aa.
  pbb=bb;    // initialize char pointer to &bb[0], using shorthand bb.

  printf("Contents of array aa[]: %s\n", paa ); // print string starting at &aa[0]
  printf("Contents of array bb[]: %s\n", pbb ); // print string starting at &bb[0]

  printf("Calling function copystr.\n");

  copystr( paa, pbb) ; // pass &aa[0] and &bb[0] to function copystr()

  printf("Contents of array bb[]: %s\n", pbb);

  return 0;
}
 
void copystr(char *str1, char *str2 ) //header: takes 2 addresses, 
                                      // assigns to char pointers str1 and str2 
                                      // returns nothing 
{
/*
 * First method 
 *
  int ii; // declare int counter
  for( ii=0; *(str1+ii) ; ii++) // initialize coutner to 0 for first element
                                // while the value at thing pointed to is not NULL
                                // do block
                                // then increment counter by 1
  {
    *(str2+ii)=*(str1+ii); // assign the value at thing pointed to in first pointer
                           // to the thing thing pointed to in second pointer
  }
  *(str2+ii)='\0';         // Add a null character at the end
  printf("End of function copystr.\n");
*/

  // K&R - Chpter 5.6
  while( *str2++ = *str1++ )   // find what is as str2 and str1
                               // assign value at str1 to str2
                               // until null
  {
    ;
  }

}