纪念逝去的岁月——C++实现一个栈

#include <stdio.h>
#include <string.h>

class ClsStack
{
private :
void ** __m_Data;
int     __m_pos;
size_t  __m_memsize;

protected :
int     __resize(size_t n);
size_t  __doublesize(size_t n);

public :
ClsStack(size_t n = 0);
~ClsStack();

int  pop(void ** ppData);
int  top(void ** ppData);
int  push(void * pData);
void clear();
};

ClsStack::ClsStack(size_t n)
{
__m_Data = NULL;
__m_pos = -1;
__m_memsize = 0;

if(0 != n)
{
__m_Data = new void *
;
if(NULL != __m_Data)
{
__m_memsize = n;
}
}
}

ClsStack::~ClsStack()
{
if(NULL != __m_Data)
{
delete __m_Data;
__m_Data = NULL;
}
__m_pos = -1;
__m_memsize = 0;
}

size_t ClsStack::__doublesize(size_t n)
{
size_t x = 0;
if(0 == n)
{
x = 1;
}
else
{
x = n * 2;
}

return x;
}

int ClsStack::__resize(size_t n)
{
void ** p = new void *
;
if(NULL == p)
{
return -1;
}
memset(p, 0, sizeof(void *) * (n));
if(NULL != __m_Data)
{
if( NULL == memcpy(p, __m_Data, __m_memsize * sizeof(void *)))
{
delete p;
return -1;
}
delete __m_Data;
}
__m_Data = p;
__m_memsize = n;

return 0;
}

int ClsStack::pop(void ** ppData)
{
if(NULL == ppData)
{
return -1;
}
int r = 0;
if(-1 == __m_pos)
{
*ppData = NULL;
r = -1;
}
else
{
*ppData = __m_Data[__m_pos --];
r = 0;
}

return r;
}

int ClsStack::top(void ** ppData)
{
if(NULL == ppData)
{
return -1;
}
int r = 0;
if(-1 == __m_pos)
{
*ppData = NULL;
r = -1;
}
else
{
*ppData = __m_Data[__m_pos];
r = 0;
}

return r;
}

int ClsStack::push(void * pData)
{
if(__m_pos + 1 >= __m_memsize)
{
size_t n = __doublesize(__m_memsize);
if(0 != __resize(n))
{
return -1;
}
}
__m_Data[++__m_pos] = pData;

return 0;
}

void ClsStack::clear()
{
if(NULL != __m_Data && 0 != __m_memsize)
{
delete __m_Data;
}
__m_Data = NULL;
__m_pos = -1;
__m_memsize = 0;
}

int main()
{
ClsStack objStack;
int x = 10;
int * p = &x;
objStack.push(p);
int i = 0;
for(i = 0; i <= 10; i++)
{
int * z = new int;
*z = i;
objStack.push(z);
}
for(i = 10; i >= 0; i--)
{
int * z = NULL;
int r = objStack.pop((void **)&z);
if(NULL == z)
{
printf("z == NULL\n");
continue;
}
if(i == *z)
{
printf("RIGHT\n");
}
else
{
printf("WRONG\n");
}
delete z;
}
int * g = NULL;
int r = objStack.pop((void **)&g);
if(x == *g)
{
printf("RIGHT\n");
}
else
{
printf("WRONG\n");
}

return 0;
}

g++ -g -o stack stack.o

RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT
RIGHT