/********************************************************************/
/* Program Assignment: Assignment 1                                 */
/* Name:               cmo                                          */
/* Date:               Oct. 18, 2004                                */
/* Descrition:         Test alias logic, unsigned chars             */
/********************************************************************/

/********************************************************************/
/* Listing Contents:                                                */
/*         General comments                                         */
/*         Reuse Instructions                                       */
/*         Compilation Instructions                                 */
/*         Source Code                                              */
/********************************************************************/

/********************************************************************/
/* General comments                                                 */
/*   Checking to see how to alias char and int arrays for the       */
/*   variable "packet"                                              */
/********************************************************************/

/********************************************************************/
/* Reuse Instructions:                                              */
/*       Limited potential                                          */
/********************************************************************/

/********************************************************************/
/* Compilation Instructions:                                        */
/*             This program can be compiled by itself using:        */
/*             g++ -l testalias -g testalias.cpp.                   */
/********************************************************************/         

using namespace std;

#include <iostream>                   //for cout statements

#include  "/home/cs350/term.projects/include.files/external.h"

struct external ex;

int main()
{

// Test chars and unsigned chars

  int tmp;
  char a;
  unsigned char b;

  cout << "testing use of chars for ints" << endl;
  cout << "enter a small int" << endl;
  cin >> tmp;
  a = tmp;
  cout << "entered value is: " << (int)a << " as char" << endl;
  cout << "5*(entered value) is " << (int)(5*a) << endl;

  cout << "enter another small int" << endl;
  cin >> tmp;
  b = tmp;
  cout << "entered value is: " << (int)b << " as unsigned char" << endl;
  cout << "5*(entered value) is " << (int)(5*b) << endl;

// Test alias ideas
  char *x;
  char *y;
  double value = 1;

  x = (char *) ex.packet;
  y = (char *) &value;

  cout << "Testing alias for char and short packet" << endl;
  cout << "  address of packet: " << x << endl;

  for ( int i=0; i<256; i++ )
    ex.packet[i] = i;

  // Print contents of beginning of packet as 8-bit ints
  for ( char i=0; i<8; i++ ) {
    tmp = *(x+i);
    cout << "i: " << (int)i << " tmp: " << tmp << endl;
    }

  // Change contents of packet through alias
  for ( int i=0; i<8; i++ )
    x[i] = 5;

  // Print contents of packet and x
  cout << "Ints & chars:" << endl;
  for ( int i=0; i<10; i++ ) {
    cout << "        x[" << 2*i << "] = " << (int) x[2*i] << endl;
    cout << "        x[" << 2*i+1 << "] = " << (int) x[2*i+1] << endl;
    cout << "ex.packet[" << i << "] = " << ex.packet[i] << endl;
  }

  // Store double in byte positions 3, 4, 5, 6, 7, 8, 9, 10 of packet
  for ( int i=0; i<8; i++ )
    x[i+3] = y[i];

  // Print beginning of packet
    cout << "Changed value of packet:" << endl;
  for ( int i=0; i<8; i++ )
    cout << "  ex.packet[" << i << "] = " << ex.packet[i] << endl;
}