a_stack.c

C和指针非常好的一本书.里面的有许多代码可以借鉴.

/*
** A stack implemented with a static array.  The array size can
** be adjusted only by changing the #define and recompiling
** the module.
*/
#include "stack.h"
#include <assert.h>

#define	STACK_SIZE	100	/* Max # of values on the stack */

/*
**	The array that holds the values on the stack, and a pointer
**	to the topmost value on the stack.
*/
static	STACK_TYPE	stack[ STACK_SIZE ];
static	int		top_element = -1;

/*
**	push
*/
void
push( STACK_TYPE value )
{
	assert( !is_full() );
	top_element += 1;
	stack[ top_element ] = value;
}

/*
**	pop
*/
void
pop( void )
{
	assert( !is_empty() );
	top_element -= 1;
}

/*
**	top
*/
STACK_TYPE top( void )
{
	assert( !is_empty() );
	return stack[ top_element ];
}

/*
**	is_empty
*/
int
is_empty( void )
{
	return top_element == -1;
}

/*
**	is_full
*/
int
is_full( void )
{
	return top_element == STACK_SIZE - 1;
}