b1__13.cxx

#include ‹stream.hxx›

// 1.11

class vector {

int *v;

int sz;

public:

vector(int); // constructor

~vector(); // destructor

int size() { return sz; }

void set_size(int);

int& operator[](int);

int& elem(int i) { return v[i]; }

};

// 1.13

class vec: public vector {

int low, high;

public:

vec(int, int);

int& elem(int);

int& operator[](int);

};

main()

{

vector a(10);

for (int i=0; i‹a.size(); i++) {

a[i] = i;

cout ‹‹ a[i] ‹‹ " ";

}

cout ‹‹ " ";

vec b(10,19);

for (i=0; i‹b.size(); i++) b[i+10] = a[i];

for (i=0; i‹b.size(); i++) cout ‹‹ b[i+10] ‹‹ " ";

cout ‹‹ " ";

}

extern void exit(int);

// 1.13

void error(char* p)

{

cerr ‹‹ p ‹‹ " ";

exit (1);

}

// 1.11

vector::vector(int s)

{

if (s‹=0) error("bad vector size");

sz = s;

v = new int[s];

}

int& vector::operator[](int i)

{

if (i‹0 || sz‹=i) error("vector index out of range");

return v[i];

}

vector::~vector()

{

delete v;

}

// 1.13

int& vec::elem(int i)

{

return vector::elem(i-low);

}

vec::vec(int lb, int hb): (hb-lb+1)

{

if (hb-lb‹0) hb = lb;

low = lb;

high = hb;

}

void vector::set_size(int) {/* dummy */}

int& vec::operator[](int i)

{

if (i‹low || high‹i) error("vec index out of range");

return elem(i);

}