# include <stdio.h>
# include <malloc.h>
# include <stdlib.h>
typedef struct Node
{
int data;
struct Node *pNext;
}NODE, *PNODE;
typedef struct Stack
{
PNODE pTop;
PNODE pBottom;//pBottem是指向栈底下一个没有实际意义的元素
}STACK, *PSTACK;
void init( PSTACK );
void push( PSTACK, int );
void traverse( PSTACK );
bool pop( PSTACK, int * );
bool empty( PSTACK pS );
int main( void )
{
STACK S;//STACK等价于struct Stack
int val;
init( &S );//目的是造出一个空栈
push( &S, 1 );//压栈
push( &S, 2 );
push( &S, 3 );
push( &S, 4 );
push( &S, 5 );
push( &S, 6 );
push( &S, 7 );
traverse( &S );//遍历输出
clear( &S ); //清空数据
traverse( &S );//遍历输出
if( pop( &S, &val ) )
{
printf( "出栈成功,出栈的元素是&d\n", val );
}
else
{
printf( "出栈失败" );
}
traverse( &S );//遍历输出
return 0;
}
void init( PSTACK pS )
{
pS->pTop = ( PNODE )malloc( sizeof( NODE ) );
if( NULL == pS->pTop )
{
printf( "动态内存分配失败!\n" );
exit( -1 );
}
else
{
pS->pBottom = pS->pTop;
pS->pTop = NULL;//或是pS->pBottom = NULL;
}
}
void push( PSTACK pS, int val )
{
PNODE pNew = ( PNODE )malloc( sizeof( NODE ) );
pNew->data = val;
pNew->pNext = pS->pTop;//pS->Top不能改为pS->pBottom
pS->pTop = pNew;
return;
}
void traverse( PSTACK pS )
{
PNODE p = pS->pTop;
while( p != pS->pBottom )
{
printf( "%d ", p->data );
p = p->pNext;
}
printf( "\n" );
return;
}
bool empty( PSTACK pS )
{
if( pS->pTop == pS->pBottom )
return true;
else
return false;
}
//把pS所指向的栈出栈一次,并把出栈的元素存入pVal形参所指向的变量中,如果出栈失败,则返回false,否则true
bool pop( PSTACK pS, int *pVal)
{
if( empty( pS ) )//pS本身存放的就是S的地址
{
return false;
}
else
{
PNODE r = pS->pTop;
*pVal = r->data;
pS->pTop = r->pNext;
free( r );
r = NULL; //为什么要把r赋给NULL呢??
return true;
}
}
//clear清空
void clear( PSTACK pS )
{
if( empty( pS ) )
{
return ;
}
else
{
PNODE p = pS->pTop;
PNODE q = p->pNext;
while( p != pS->pBottom )
{
q = p->pNext;
free( p );
p = q;
}
pS->pTop = pS->pBottom;
}
}
本文出自 “Linux运维” 博客，请务必保留此出处http://2853725.blog.51cto.com/2843725/1379904
原文：http://2853725.blog.51cto.com/2843725/1379904