1 /**

     2  * DEREFERNCING CLASSES

     3  */

     4 

     5 #include <cstdio>

     6 #include <cstdlib>

     7 #include <cmath>

     8 #include <ctime>

     9 

    10 #define GETRANDOM(max) (1+(int)((float)max*rand()/RAND_MAX+1.0))

    11 #define MAX 6

    12 

    13 namespace algebra {

    14     class Vector {

    15       private:

    16         int x;

    17         int y;

    18 

    19       public:

    20         Vector (int xx = 0, int yy = 0);

    21        ~Vector ();

    22 

    23         int X () { return x; }

    24         int Y () { return y; }

    25 

    26         Vector operator+ (Vector&);

    27         Vector operator- (Vector&);

    28 

    29         void vector ();

    30         double abs ();

    31     };

    32 

    33     Vector::Vector (int xx, int yy) {

    34         x = xx;

    35         y = yy;

    36     }

    37 

    38     Vector::~Vector () {

    39         fprintf (stderr, "Removing Vector (%.3d, %.3d)\n", x, y);

    40     }

    41 

    42     Vector Vector::operator+ (Vector& v) {

    43         return Vector (x + v.X (), y + v.Y ());

    44     }

    45 

    46     Vector Vector::operator- (Vector& v) {

    47         return Vector (x - v.X (), y - v.Y ());

    48     }

    49 

    50     double Vector::abs () {

    51         return sqrt (x * x + y * y);

    52     }

    53 

    54     void Vector::vector () {

    55         printf ("(%.3d, %.3d)", x, y);

    56     }

    57 }

    58 

    59 using namespace algebra;

    60 

    61 int main (int argc, char **argv)

    62 {

    63     Vector *v[MAX];

    64     Vector result;

    65 

    66     srand (time (NULL));

    67 

    68     if ((MAX % 2) != 0) {

    69         printf ("MAX %% 2 != 0\n");

    70         return EXIT_FAILURE;

    71     }

    72 

    73     for (int i = 0; i < MAX; i++) {

    74         v[i] = new Vector (GETRANDOM (100), GETRANDOM (100));

    75     }

    76 

    77     for (int i = 0; i < MAX; i += 2) {

    78         v[i + 1]->vector ();

    79         printf ("+");

    80         v[i]->vector ();

    81         printf ("=");

    82         result = *v[i + 1] + *v[i];

    83         result.vector ();

    84         printf (" = %3.2f\n", result.abs ());

    85     }

    86 

    87     printf ("\n");

    88 

    89     for (int i = 0; i < MAX; i += 2) {

    90         v[i + 1]->vector ();

    91         printf ("-");

    92         v[i]->vector ();

    93         printf ("=");

    94         result = *v[i + 1] - *v[i];

    95         result.vector ();

    96         printf (" = %3.2f\n", result.abs ());

    97     }

    98 

    99     printf ("\nCLEANUP\n");

   100 

   101     for (int i = 0; i < MAX; i++)

   102         delete v[i];

   103 

   104     return EXIT_SUCCESS;

   105 }