/
11-0.cpp
130 lines (100 loc) · 2.71 KB
/
11-0.cpp
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#include <iostream>
#include <memory>
#include <algorithm>
using std::allocator;
using std::cout;
using std::endl;
using std::max;
using std::uninitialized_copy;
using std::ptrdiff_t;
template <class T> class Vec {
public:
typedef T* iterator;
typedef const T* const_iterator;
typedef size_t size_type;
typedef T value_type;
typedef T& reference;
typedef const T& const_reference;
Vec() { create(); } // default constructor
explicit Vec(size_type n, const T& t = T()) { create(n, t); }
Vec(const Vec& v) { create(v.begin(), v.end()); } // copy constructor
Vec& operator=(const Vec&);
~Vec() {uncreate(); }
T& operator[](size_type i) { return data[i]; }
const T& operator[](size_type i) const { return data[i]; }
void push_back(const T& t) {
if (avail == limit)
grow();
unchecked_append(t);
}
size_type size() const { return avail - data; }
iterator begin() { return data; }
const_iterator begin() const { return data; }
iterator end() { return avail; }
const_iterator end() const { return avail; }
private:
iterator data;
iterator avail;
iterator limit;
allocator<T> alloc;
void create();
void create(size_type, const T&);
void create(const_iterator, const_iterator);
void uncreate();
void grow();
void unchecked_append(const T&);
};
template <class T> void Vec<T>::create()
{
data = avail = limit = 0;
}
template <class T> void Vec<T>::create(size_type n, const T& val)
{
data = alloc.allocate(n);
limit = avail = data + n;
uinitialized_fill(data, limit, val);
}
template <class T>
void Vec<T>::create(const_iterator i, const_iterator j)
{
data = alloc.allocate(j - i);
limit = avail = unitialized_copy(i, j, data);
}
template <class T> void Vec<T>::uncreate()
{
if (data) {
iterator it = avail;
while (it != data)
alloc.destroy(--it);
alloc.deallocate(data, limit - data);
}
data = limit = avail = 0;
}
template <class T> void Vec<T>::grow()
{
size_type new_size = max(2 * (limit - data), ptrdiff_t(1));
iterator new_data = alloc.allocate(new_size);
iterator new_avail = uninitialized_copy(data, avail, new_data);
uncreate();
data = new_data;
avail = new_avail;
limit = data + new_size;
}
template <class T> void Vec<T>::unchecked_append(const T& val)
{
alloc.construct(avail++, val);
}
int main()
{
Vec<int> ages;
ages.push_back(31);
ages.push_back(60);
ages.push_back(36);
ages.push_back(14);
ages.push_back(0);
Vec<int>::size_type n = ages.size();
ages[n-1] = 7;
for (Vec<int>::size_type i = 0; i != n; i++)
cout << ages[i] << endl;
return 0;
}