#include<stdio.h>
#include<stdlib.h>
#define MAX 20
typedef struct{
	char stack[MAX];
	int top;
}symbol_instr;
//初始化棧
void init_stack(symbol_instr *p)
{
	if( !p)
		printf("\n初始化符號(hào)棧出錯(cuò)!\n");
	p->top = -1;
}
//壓棧
void push(symbol_instr *p,char x)
{
	if(p->top < MAX-1)
	{
		p->top++;
		p->stack[p->top] = x;
	}
	else printf("\n符號(hào)棧溢出!\n");
}
//彈棧
char pop(symbol_instr *p)
{
	char x;
	if(p->top != -1)
	{
		x = p->stack[p->top];
		p->top--;
		return x;
	}
	else 
	{
		printf("\n符號(hào)棧1空!\n");
		return 0;
	}
}
//取棧頂元素
char get_top(symbol_instr *p)
{
	char x;
	if(p->top != -1)
	{
		x = p->stack[p->top];
		return x;
	}
	else 
	{
		printf("\n符號(hào)棧2空!\n");
		return 0;
	}
}
//自棧底到棧頂遍歷棧元素
void out_stack1(symbol_instr *p)
{
	int i;
	if(p->top <0)
		printf("\n符號(hào)棧3空!\n");
	for(i=0; i<=p->top;i++)
	{
		printf("%c",p->stack[i]);
	}
}
//自棧頂?shù)綏５妆闅v棧元素
void out_stack2(symbol_instr *p)
{
	int i;
	if(p->top <0)
		printf("\n符號(hào)棧4空!\n");
	for( i=p->top;i>=0;i--)
	{
		printf("%c",p->stack[i]);
	}
}