简单顺序栈（C++模版技术实现）

//
// C++ 模版技术实现简单顺序栈.
//

#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <stdexcept>

//
// 顺序栈类模版.
//
template <typename T>
class Stack
{
private:
int _top;
size_t _size;
T *_pStack;
static const size_t _DEF_SIZE = 20;
//
// _MIN_TOP 不应为 size_t 类型.
// 因为 size_t 类型与 int 类型变量比较时会将 int 类型转换为 size_t 类型.
//
static const int _MIX_TOP = 0;

public:
Stack(const size_t size = _DEF_SIZE)
: _top(_MIX_TOP - 1)
, _size(size)
{ _pStack = new T[_size]; }

~Stack(void)
{ delete[] _pStack; }

bool isEmpty(void) const
{ return _MIX_TOP > _top; }

bool isFull(void) const
{ return _size - 1 == _top; }

T getTop(void) const
{
if (isEmpty()) {
throw std::underflow_error("栈空下溢 !");
}
return _pStack[_top];
}

void push(const T &val)
{
if (isFull()) {
throw std::overflow_error("栈满上溢 !");
}
_pStack[++_top] = val;
}

T pop(void)
{
if (isEmpty()) {
throw std::underflow_error("栈空下溢 !");
}
return _pStack[_top--];
}
};

//
// 测试栈.
//
int main(void)
{
const size_t MAX_SIZE = 20;
Stack<int> stack(MAX_SIZE);

std::cout << "栈" << (stack.isEmpty() ? "" : "不") << "为空." << std::endl;
std::cout << "栈" << (stack.isFull() ? "" : "不") << "为满." << std::endl;

for (size_t i = 0; i < MAX_SIZE; ++i)
{
stack.push(i);
std::cout << std::setw(3) << stack.getTop();
}
// stack.push(MAX_SIZE);

std::cout << std::endl;
std::cout << "栈" << (stack.isEmpty() ? "" : "不") << "为空." << std::endl;
std::cout << "栈" << (stack.isFull() ? "" : "不") << "为满." << std::endl;

for (size_t i = 0; i < MAX_SIZE; ++i)
{
std::cout << std::setw(3) << stack.pop();
}
// std::cout << std::setw(3) << stack.pop();

return EXIT_SUCCESS;
}