symbol_instr_stack.h

编译原理的实验

#include<stdio.h>
#include<stdlib.h>
#define MAX 20
typedef struct{
	char stack[MAX];
	int top;
}symbol_instr;
//初始化栈
void init_stack(symbol_instr *p)
{
	if( !p)
		printf("\n初始化符号栈出错!\n");
	p->top = -1;
}
//压栈
void push(symbol_instr *p,char x)
{
	if(p->top < MAX-1)
	{
		p->top++;
		p->stack[p->top] = x;
	}
	else printf("\n符号栈溢出!\n");
}
//弹栈
char pop(symbol_instr *p)
{
	char x;
	if(p->top != -1)
	{
		x = p->stack[p->top];
		p->top--;
		return x;
	}
	else 
	{
		printf("\n符号栈1空!\n");
		return 0;
	}
}
//取栈顶元素
char get_top(symbol_instr *p)
{
	char x;
	if(p->top != -1)
	{
		x = p->stack[p->top];
		return x;
	}
	else 
	{
		printf("\n符号栈2空!\n");
		return 0;
	}
}
//自栈底到栈顶遍历栈元素
void out_stack1(symbol_instr *p)
{
	int i;
	if(p->top <0)
		printf("\n符号栈3空!\n");
	for(i=0; i<=p->top;i++)
	{
		printf("%c",p->stack[i]);
	}
}
//自栈顶到栈底遍历栈元素
void out_stack2(symbol_instr *p)
{
	int i;
	if(p->top <0)
		printf("\n符号栈4空!\n");
	for( i=p->top;i>=0;i--)
	{
		printf("%c",p->stack[i]);
	}
}