#include<stdio.h>  
#include<windows.h>  
#include<malloc.h>  
#define maxsize 50  
typedef int elemtype;  
typedef struct //定义  
{  
elemtype data[maxsize];  
int top;  
}sqstack;  
void initstack(sqstack *&s) //初始化  
{  
s=(sqstack *)malloc(sizeof(sqstack));  
s->top=-1;  
}  
void push(sqstack *&s) //进栈  
{  
char e;  
getchar();  
printf("请输入需进栈的元素:");  
scanf("%c",&e);  
if(s->top>maxsize-1)  
printf("栈满，错误!
");  
else  
{  
s->top++;  
s->data[s->top]=e;  
printf("进栈成功
");  
}  
}  
void gettop(sqstack *s) //取栈顶元素  
{  
char t;  
if(s->top==-1)  
printf("栈空，取值失败!
");  
else  
{  
t=s->data[s->top];  
printf("取值成功，栈顶元素为:%c
",t);  
}  
}  
void stackempty(sqstack *s) //判断栈是否为空  
{  
if(s->top==-1)  
printf("栈为空
");  
else  
printf("栈不为空
");  
}  
void pop(sqstack *&s) //出栈  
{  
char e;  
if(s->top==-1)  
printf("栈为空，出栈失败
");  
else  
{  
e=s->data[s->top];  
s->top--;  
printf("出栈成功，出栈元素为:%c
",e);  
}  
}  
int length(sqstack *s) //求栈长  
{  
if(s->top==-1)  
return(-1);  
else  
return(s->top+1);  
}  
void destroy(sqstack *&s) //销毁栈  
{  
char t;  
getchar();  
printf("确定要销毁栈请输入y 否则不销毁:");  
scanf("%c",&t);  
if(t=="y")  
{  
free(s);  
printf("销毁成功
");  
exit(0);  
}  
else  
printf("栈未销毁
");  
  
}  
void output(sqstack *s)  
{  
int m,n=s->top;  
m=length(s)+1;  
if(s->top==-1)  
printf("栈为空
");  
else  
{  
printf("出栈序列为:");  
for(;m>0;m--)  
{  
printf(" %c",s->data[s->top]);  
s->top--;  
}  
printf("
");  
s->top=n;  
}  
}  
void main()  
{  
sqstack *s;  
printf(" ************欢迎使用顺序栈运算系统*************
");  
int m;  
initstack(s);  
while(1)  
{  
printf("请选择:");  
printf(" 1 进栈
");  
printf(" 2 判断栈是否为空
");  
printf(" 3 取栈顶元素
");  
printf(" 4 出栈
");  
printf(" 5 销毁栈
");  
printf(" 6 求栈的长度
");  
printf(" 7 输出出栈序列
");  
printf(" 8 退出
");  
scanf("%d",&m);  
switch(m)  
{  
case 1:push(s);break;  
case 2:stackempty(s);break;  
case 3:gettop(s);break;  
case 4:pop(s);break;  
case 5:destroy(s);break;  
case 6:printf("栈的长度为%d
",length(s));break;  
case 7:output(s);break;  
case 8:exit(0);  
default:printf("输入错误,请重新输入
");  
}  
}  
}