栈的简单基本操作（数据结构）

#include<stdio.h>
#include<stdlib.h>
#define STACK_INIT_SIZE 100
#define STACKINCREMENT 10
#define ERROR 0
#define OK 1
#define OVERFLOW -1

typedef char SElemType;

typedef struct{
SElemType *base;
SElemType *top;
int stacksize;
}SqStack;

int InitStack(SqStack *S){
S->base=(SElemType*)malloc(STACK_INIT_SIZE*sizeof(SElemType));
if(!S->base) exit(OVERFLOW);
S->top=S->base;
S->stacksize=STACK_INIT_SIZE;
return OK;
}

int GetTop(SqStack *S){
char e;
if(S->top==S->base) return ERROR;
e=*(S->top-1);
printf("the top element is %c\n",e);
return OK;

}

int Push(SqStack *S,SElemType e){
if(S->top-S->base>=S->stacksize){
S->base=(SElemType *)realloc(S->base,(S->stacksize+STACKINCREMENT)*sizeof(SElemType));
if(!S->base) exit(OVERFLOW);
S->top=S->base+S->stacksize;
S->stacksize+=STACKINCREMENT;
}
*S->top++=e;
return OK;
}

SElemType Pop(SqStack *S){
SElemType e;
if(S->top==S->base) printf("ERROR!!!");
e=*--S->top;
return e;

}

void main(){
SqStack S;
char ch[5];
int i;
SElemType e;
if(InitStack(&S)==1) printf("creat stack succeed!\n");
else printf("creat stack failed!\n");
for(i=0;i<5;i++){
printf("input the %d element\n",i);
scanf("%c",&ch[i]);
getchar();

}
for(i=0;i<5;i++)
Push(&S,ch[i]);

if(GetTop(&S)==1) printf("get stack top succeed!\n");
else printf("get stack top failed!\n");

e=Pop(&S);
printf("the pop element is %c\n",e);
e=Pop(&S);
printf("the top element is %c\n",e);

}