ice cream

<<ICE CREAM>>

关于pthread相关函数基本内容，查看下面的文章

pthread 基本内容

重点补充：pthread_join(pthread_t threadl,void **rval_ptr);这个函数主要用在保证创建的线程可以被执行完，主程序在退出。

建设由主程序创建线程a,在主程序中执行pthread_join（a,NULL）主程序会在线程a执行完毕后，主程序在退出，避免因为时间片的切换，导致主程序执行完毕直接推出，而线程还没有执行完已经因为主程序的推出，而不能继续执行，主程序会被阻塞在该语句处，不能继续执行，直到线程a执行完毕，主程序在继续执行。

关于semaphore 相关内容参考下面文章

semaphore 信号量

关于讲解 icecream的视频 http://open.163.com/movie/2008/1/6/5/M6SL23BRS_M6SL3BD65.html

实现代码：

#include <stdio.h>
#include <semaphore.h>
#include <pthread.h>

#define NUM_CUSTOMESS 10

struct ManCler {
	int Result;
	sem_t Request ;
	sem_t Finished;
	sem_t Lock;
} Mess_Man_Cler;
/*struct ManCler Mess_Man_Cler;
Mess_Man_Cler.Result = 0 ; 
sem_init(&(Mess_Man_Cler.Request),0,0);
sem_init(&(Mess_Man_Cler.Finshed),0,0);
sem_init(&(Mess_Man_Cler.Lock),0,1);
*/
struct CashCustom{
	int n ;
	sem_t Request ;
	sem_t Customsequence[NUM_CUSTOMESS];
	sem_t Lock;
}Cash_Custom;
/*Cash_Custom.n = 0;
sem_init(&(Cash_Custom.Requst),0,0);
//sem_init(&Cash_Custom.ClerkFinish,0,0);
sem_init(&(Cash_Custom.Lock),0,1);
for (int i = 0 ; i < NUM_CUSTOMESS ; i++)
{
	sem_init(&(Cash_Custom.Customsequencd)+i,0,0);
}
*/
void* manager(void * TotalCustom);
void* customes(void * NumIceCream);
void* clerk(void*ClerkFinished);
void* cashier();
void Initial();

void Initial(){
	Mess_Man_Cler.Result = 0 ; 
	sem_init(&(Mess_Man_Cler.Request),0,0);
	sem_init(&(Mess_Man_Cler.Finished),0,0);
	sem_init(&(Mess_Man_Cler.Lock),0,1);

	Cash_Custom.n = 0;
	sem_init(&(Cash_Custom.Request),0,0);
	sem_init(&(Cash_Custom.Lock),0,1);
	for (int i = 0 ; i < NUM_CUSTOMESS ; i++)
	{
		sem_init(&(Cash_Custom.Customsequence[i]),0,0);
	}
}


void* customes(void * NumIceCream)
{	
	int place;
	sem_t ClerkFinished;
	sem_init(&(ClerkFinished),0,0);

	int p = *(int*)NumIceCream;
	printf("cusomes:all number of ice cream %d\n",p);
	for (int i = 0; i < p; i++)
	{	
		//char c[32] ;
		//sprintf(c,"clerk %d",i);
		pthread_t a;
		pthread_create(&a,NULL,clerk,(void *)(&ClerkFinished));
	}
	printf("custom:i employ all clerk\n");
	for (int i = 0;i < p ; i++ ) sem_wait(&ClerkFinished);//这句话是等待clerk完成相关功能，即等待p个clerk都完成相关功能，每个clerk完成一次功能后，for循环由被阻塞的状态变成可以执行一次，然后继续被阻塞，p个 clerk完成相关功能后。for循环执行完毕。
	printf("custome :i get all the ice cream");
	sem_destroy(&ClerkFinished);
	sem_wait(&(Cash_Custom.Lock));
	place = Cash_Custom.n++;
	sem_post(&(Cash_Custom.Lock));
	sem_post(&(Cash_Custom.Request));
	sem_wait(&(Cash_Custom.Customsequence[place]));
	printf("cusome:i finished my shopping\n");
}

void*cashier()
{
	for (int i = 0;i < NUM_CUSTOMESS;i++)
	{
		sem_wait(&(Cash_Custom.Request));
		printf("cashier:%d is checked\n",i);
		sem_post(&(Cash_Custom.Customsequence[i]));	
	}
	
}


void* manager(void * TotalCustom)
{
	int TotalNumber = *(int*)TotalCustom;
	int approve = 0;
	while (approve < TotalNumber)
	{
		sem_wait(&(Mess_Man_Cler.Request));
		Mess_Man_Cler.Result = rand()%2;
		if (Mess_Man_Cler.Result == 1) approve += 1;
		printf("manager:manager finshed check\n");
		sem_post(&Mess_Man_Cler.Finished);
	}
	printf("manage:exit()");	
}
void* clerk(void * ClerkFinished)
{
	int p = 0;// used to descipe the initail stata of the Result
	while(p != 1)
	{
		printf("clerk:clerk finins a ice cream\n");
		sem_wait(&(Mess_Man_Cler.Lock));
		sem_post(&(Mess_Man_Cler.Request));
		sem_wait(&(Mess_Man_Cler.Finished));
		p = Mess_Man_Cler.Result;
		sem_post(&(Mess_Man_Cler.Lock));	
	}
	sem_post((sem_t*)(ClerkFinished));
	printf("clerk:clerk finished the ice cream\n");
}




int main(){
	Initial();	
	int TotalIceCream = 0;//record the number of the ice cream needed by allclerk
	int NumIceCream[NUM_CUSTOMESS] ;
	for (int i = 0; i < NUM_CUSTOMESS;i++)
	{
		NumIceCream[i] = rand()%4 + 1;
	}
	pthread_t ArrayCustom[NUM_CUSTOMESS];//the name of thread custom
	pthread_t P_Manager = 0;//the name of thread mamager
	pthread_t P_Cashier = 0;//the name of thread cashier
	for(int i = 0;i < NUM_CUSTOMESS;i++){
		//NumIceCream = rand()%4+1;
		pthread_create(ArrayCustom+i,NULL,customes,(void*)(NumIceCream+i));
		TotalIceCream += NumIceCream[i];
		printf("%d ice cream\n", NumIceCream[i]);
	}	
		printf("totalNumbes:%d\n",TotalIceCream);
	pthread_create(&P_Manager,NULL,manager,(void*)&TotalIceCream);
	pthread_create(&P_Cashier,NULL,cashier,NULL);
        //printf("99999");
	
	for(int i;i < NUM_CUSTOMESS;i++)
	{
		pthread_join(ArrayCustom[i],NULL);	
	}
	pthread_join(P_Manager,NULL);
	pthread_join(P_Cashier,NULL);


}