C++ 練習:用指針實現棧

使用C++的指針實現一個簡單版的棧

stack.h

 

#ifndef stack_hpp
#define stack_hpp

#include <stdio.h>

class Stack
{
public:
    Stack();
    ~Stack();
    
    bool Push(int value);
    int Pop();
    
private:
    unsigned int m_elem_size;
    unsigned int m_logic_length;
    unsigned int m_alloc_length;
    int* m_elems;
};
#endif /* stack_hpp */

stack.cpp

 

 

#include "stack.hpp"
#include <stdlib.h>
#include <assert.h>

Stack::Stack()
{
    m_elem_size = sizeof(int);
    m_logic_length = 0;
    m_alloc_length = 4;
    
    m_elems = (int*)malloc(m_alloc_length * sizeof(m_elem_size));
}

Stack::~Stack()
{
    free(m_elems);
}

bool Stack::Push(int value)
{
    //如果棧已滿，根據翻倍策略擴大內存
    if(m_logic_length == m_alloc_length)
    {
        m_alloc_length = m_alloc_length * 2;
        m_elems = (int*)realloc(m_elems, m_alloc_length * m_elem_size);
        assert(m_elems != NULL);
    }
    
    m_elems[m_logic_length] = value;
    m_logic_length ++;
    
    return true;
}

int Stack::Pop()
{
    assert(m_logic_length > 0);
    m_logic_length --;
    return m_elems[m_logic_length];
}

main.cpp

 

 

#include "stack.hpp"
#include <iostream>

int main(int argc, const char * argv[]) {
    
    Stack stack;
    stack.Push(1);
    stack.Push(2);
    stack.Push(3);
    stack.Push(4);
    stack.Push(5);
    
    int val = stack.Pop();
    std::cout << "val" << val << std::endl;
    
    return 0;
}