b5_3_2.cxx

b5_3_2.cxx

#include ‹stream.hxx›

class intset {

 int cursize, maxsize;

 int *x;

public:

 intset(int m, int n);

 ~intset();

 int member(int t);

 void insert(int t);

 void iterate(int& i) { i = 0; }

 int ok(int& i) { return i‹cursize; }

 int next(int& i) { return x[i++]; }

};

extern void exit (int);

void error(char *s)

{

 cout ‹‹ "set: " ‹‹ s ‹‹ " ";

 exit(1);

}

extern int atoi(char *);

extern int rand();

int randint (int u) // in the range 1…u

{

 int r = rand();

 if (r ‹ 0) r = -r;

 return 1 + r%u;

}

intset::intset(int m, int n)

{

 if (m‹1 || n‹m) error("illegal intset size");

 cursize = 0;

 maxsize = m;

 x = new int[maxsize];

}

intset::~intset()

{

 delete x;

}

void intset::insert(int t)

{

 if (++cursize › maxsize) error("too many elements");

 int i = cursize-1;

 x[i] = t;

while (i›0 && x[i-1]›x[i]) {

 int t = x[i];

 x[i] = x[i-1];

 x[i-1] = t;

 i--;

 }

}

int intset::member(int t)

{

 int l = 0;

 int u = cursize-1;

 int m =0;

 while (l ‹= u) {

  m = (l+u)/2;

  if (t ‹ x[m])

   u = m-1;

  else if (t › x[m])

   l = m+1;

  else

   return 1; // found

 }

 return 0; // not found

}

void print_in_order(intset* set)

{

 int var;

 set-›iterate(var);

 while (set-›ok(var)) cout ‹‹ set-›next(var) ‹‹ " ";

}

main (int argc, char *argv[])

{

 if (argc!= 3) error("two arguments expected");

 int count = 0;

 int m = atoi(argv[1]);

 int n = atoi (argv[2]);

 intset s(m,n);

 int t = 0;

 while (count ‹m) {

  t = randint(n);

  if (s.member(t)==0) {

   s.insert(t);

   count++;

  }

 }

 print_in_order(&s);

}