这个算是数据结构的内容讲解的是一个叫做栈类型的数据结构,这个数据结构的特点就是后进先出--最后放进去的数据最先拿出来。pop函数就是拿出数据的操作,push是放入是数据的操作。
内容拓展:
pop函数呵push函数的使用:
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
void *clean(void *arg)
{
printf("cleanup: %s \n",(char *)arg)
return (void *)0
}
void * thr_fn1(void * arg)
{
printf("chread 1 start \n")
pthread_cleanup_push((void *)clean,"thraed 1 first handler")
pthread_cleanup_push((void *)clean,"thread 1 second handler")
printf("thread 1 push complete \n")
if(arg)
{
return ((void *)1)
}
pthread_cleanup_pop(0)
pthread_cleanup_pop(0)
return (void *)1
}
//输出结果: chread 1 start ->thread 1 push complte
//push和pop框起来的代码,不管正常退出还是异常退出,都将执行清除函数,但是存在特例:不包括return 退出。
#include <stdio.h>#include <stdlib.h>
#define MAXSIZE 32
typedef struct{
int *elem/* 栈的存储区 */
int max /* 栈的容量,即找中最多能存放的元素个数 */
int top /* 栈顶指针 */
}Stack
int InitStack(Stack *S, int n) /*创建容量为n的空栈*/
{
S->elem = (int *)malloc(n * sizeof(int))
if(S->elem==NULL) return -1
S->max=n
S->top =0 //栈顶初值0
return 0
}
int Push(Stack *S, int item) /*将整数item压入栈顶*/
{
if(S->top==S->max) {
printf("Stack is full! \n")
return -1
}
S->elem[S->top++] = item //压栈,栈顶加1
return 0
}
int StackEmpty(Stack S)
{
return (!S.top)?1:0 /*判断栈是否为空*/
}
int Pop(Stack *S) /*栈顶元素出栈*/
{
if(!S->top) {
printf("Pop an empty stack!\n")
return -1
}
return S->elem[--S->top] //弹出栈,栈顶减1
}
void MultibaseOutput(long n,int B)
{
int m Stack S
if(InitStack(&S,MAXSIZE)){
printf("Failure!\n")
return
}
do {
if (Push(&S,B )) //------
{
printf("Failure!\n")
return
}
n= n-1 //--------
}while(n!=0)
while(!StackEmpty(S)) { /*输出B进制的数*/
m=Pop(&S)
if(m<10) printf("%d",m) /*小于10,输出数字*/
else printf("%c", m+55) /*大于或等于10,输出相应的字符*/
}
printf("\n")
}
在keil C51中,直接调用库函数:#include<intrins.h>// 其中包含了对部分汇编指令的调用申明
_nop_()// 产生一条NOP指令
_push_(acc)// 产生一条push指令
以下是intrins.h的内容
/*--------------------------------------------------------------------------
INTRINS.H
Intrinsic functions for C51.
Copyright (c) 1988-2004 Keil Elektronik GmbH and Keil Software, Inc.
All rights reserved.
--------------------------------------------------------------------------*/
#ifndef __INTRINS_H__
#define __INTRINS_H__
extern void _nop_ (void)
extern bit _testbit_ (bit)
extern unsigned char _cror_(unsigned char, unsigned char)
extern unsigned int _iror_(unsigned int, unsigned char)
extern unsigned long _lror_(unsigned long, unsigned char)
extern unsigned char _crol_(unsigned char, unsigned char)
extern unsigned int _irol_(unsigned int, unsigned char)
extern unsigned long _lrol_(unsigned long, unsigned char)
extern unsigned char _chkfloat_(float)
extern void _push_(unsigned char _sfr)
extern void _pop_ (unsigned char _sfr)
#endif