栈的数组表示

数据结构刚学完这点，还是觉的用链表比较好。

//array for stack
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define DEFSIZE 20

typedef char ELEMTYPE;//top&base's type can be changed for use
typedef struct
{
ELEMTYPE *base;
ELEMTYPE *top;
int stackSize;
}SQSTACK,*SQSTACKP;

SQSTACKP initstack(SQSTACKP sqstack);
int isfull(SQSTACKP sqstack);
int isempty(SQSTACKP sqstack);
int push(SQSTACKP sqstack,ELEMTYPE elem);
ELEMTYPE pop(SQSTACKP sqstack);
ELEMTYPE gettop(SQSTACKP sqstack);
int addroom(SQSTACKP sqstack,int howmuch);

void main()
{
SQSTACKP stack=NULL;
char i = 48;
stack=initstack(stack);

while(i<=67)
push(stack,i++);

while(isempty(stack)!=1)
{
printf("%d\n",pop(stack));
i--;
}

getchar();

free((*stack).base);
free(stack);
}

SQSTACKP initstack(SQSTACKP sqstack)//initialise
{
sqstack=(SQSTACKP)malloc(sizeof(SQSTACK));
if(!sqstack) return NULL;
(*sqstack).base=(ELEMTYPE*)malloc(DEFSIZE*sizeof(ELEMTYPE)+1);//one more nod as final,avoid wild pointer
if(!(*sqstack).base) return NULL;
(*sqstack).top=(*sqstack).base;
(*sqstack).stackSize=DEFSIZE;
return sqstack;
}//initstack

int isfull(SQSTACKP sqstack)//full return 1,not full return -1
{
if((*sqstack).top==((*sqstack).base+(*sqstack).stackSize)) return 1;//full condition
return -1;
}//isfull

int isempty(SQSTACKP sqstack)//empty return 1,not empty return -1
{
if((*sqstack).base==(*sqstack).top) return 1;
return -1;
}//isempty

int push(SQSTACKP sqstack,ELEMTYPE elem)//success return 1,fail return -1
{
if(isfull(sqstack)==1)
if(addroom(sqstack,5)==-1) return -1;
*(*sqstack).top++=elem;
return 1;
}//push

ELEMTYPE pop(SQSTACKP sqstack)
{
if(isempty(sqstack)==1) return '#';//error return '#'
return *--(*sqstack).top;
}//pop

ELEMTYPE gettop(SQSTACKP sqstack)
{
if(isempty(sqstack)==1) return '#';
return *((*sqstack).top-1);
}//gettop

int addroom(SQSTACKP sqstack,int howmuch)
{
void *temp;
if((*sqstack).stackSize>=1000) return -1;//too much memory is not allowed
temp=(ELEMTYPE*)realloc((*sqstack).base,sizeof(ELEMTYPE)*((*sqstack).stackSize+howmuch+1));
if(!temp) return -1;
(*sqstack).base=temp;
(*sqstack).stackSize=(*sqstack).stackSize+howmuch;
return 1;
}//addroom



以后会附上一些用栈的算法。
欢迎批评指正。