吃水果问题的模拟程序

题目：

有一个盘子，可以放5个水果（苹果or桔子）。父亲每次向盘子随机放入一个水果（苹果or桔子），父亲放入水果的次数不少于11次。儿子只吃桔子，女儿只吃苹果。请编程使用信号量机制模拟解决此进程同步问题。打印信息包括盘子的情况、调度的情况以及父亲、儿子或者女儿执行的操作。

思路描述：

构造一个循环链表来模拟缓冲区的队列，两个移动的指针，一个代表儿子和女儿，一个代表父亲。当出现空盘时阻塞儿子和女儿，当盘子里出现了儿子和女儿要吃的的东西的时候唤醒他们，当盘子满了的时候，阻塞父亲，因为量比较小就没有构造阻塞队列了，直接用了个标志数组。

<span style="font-size:18px;">#include<stdio.h>
#include<time.h>

//定义表示盘子的结构体
struct Fruit {
int kind;//0表示空盘，1表示苹果，2表示橘子
struct Fruit*next;
};

//表示三者各自是否处于阻塞状态
//int sonBlockedFlag = 0;//1表示blocked，0表示ready
//int daughterBlockedFlag = 0;//1表示blocked，0表示ready
//int fatherBlockedFlag = 0;

//1表示blocked，0表示ready
//block[0],block[1],block[2]分别表示父亲，儿子，女儿
int block[3];

//传入可放水果的个数
//构造一个循环链表来模拟缓冲区的队列
struct Fruit *initFruit(int num) {
int i;
if(num == 0) {
return;
}
struct Fruit *head = (struct Fruit*)malloc(sizeof(struct Fruit));
struct Fruit *p = head,*q;
for(i = 0;i < num;i++) {
q = (struct Fruit*)malloc(sizeof(struct Fruit));
q->kind = 0;//开始都是空盘
p->next = q;
p = q;
}
q->next = head;
return head;
}

//用来打印盘子现在的转态
void showPlate(struct Fruit *head) {
if(!head) {
return;
}
struct Fruit *p = head->next;
printf("plate: |");
while(p != head) {
if(p->kind == 0) {
printf(" |");
p = p->next;
} else {
if(p->kind == 1) {
printf("A|");
p = p->next;
} else {
printf("O|");
p = p->next;
}
}
}
printf("\n\n");
}

int main() {
struct Fruit *head = initFruit(5);//题目中说可以放5个水果
int schedulingCount,i;
printf("Please input scheduling count:");
scanf("%d",&schedulingCount);
//两个移动的指针，一个代表儿子和女儿，一个代表父亲
struct Fruit *sonOrDaughter = head;
struct Fruit *father = head;
int choice1;//用来存放产生的随机数，0调度父亲，1调度儿子，2调度女儿
int choice2;//用来存放产生的随机数，0放苹果，1放橘子
srand((unsigned)time(NULL));
for(i = 0;i < schedulingCount;i++) {
//从未阻塞部分选取
do {
choice1 = rand()%3;
}while(block[choice1]);
if(choice1 == 0) {
printf("sched: father\n");
if(father->next == head) {
father = father->next;
}
if(father->next->kind != 0) {
printf("father: full, blocked me\n\n");
block[0] = 1;
} else {
choice2 = rand()%2;
if(choice2 == 0) {
father->next->kind = 1;
printf("father: put an 'A'pple\n");
father = father->next;
if(block[2] == 1) {
block[2] = 0;
printf("daughter:awake me!\n");
}
showPlate(head);
} else {
father->next->kind = 2;
printf("father: put an 'O'range\n");
father = father->next;
if(block[1] == 1) {
block[1] = 0;
printf("son:awake me!\n");
}
showPlate(head);
}
}
} else {
if(choice1 == 1) {
printf("sched: son\n");
if(sonOrDaughter->next == head) {
sonOrDaughter = sonOrDaughter->next;
}
if(sonOrDaughter->next->kind == 0) {
printf("son: not orange, blocked me\n\n");
block[1] = 1;
//				if(block[0]) {
//						printf("father:awake me!\n");
//					}
} else {
if(sonOrDaughter->next->kind == 1) {
printf("son: not orange\n\n");
} else {
printf("son: eat an orange\n");
sonOrDaughter->next->kind = 0;
sonOrDaughter = sonOrDaughter->next;
if(block[0]) {
block[0] = 0;
printf("father:awake me!\n");
}
showPlate(head);
}
}
} else {
printf("sched: daughter\n");
if(sonOrDaughter->next == head) {
sonOrDaughter = sonOrDaughter->next;
}
if(sonOrDaughter->next->kind == 0) {
printf("daughter: not orange, blocked me\n\n");
block[2] = 1;
//				if(block[0]) {
//						printf("father:awake me!\n");
//					}
} else {
if(sonOrDaughter->next->kind == 2) {
printf("daughter: not Apple\n\n");
} else {
printf("daughter: eat an Apple\n");
sonOrDaughter->next->kind = 0;
sonOrDaughter = sonOrDaughter->next;
if(block[0]) {
block[0] = 0;
printf("father:awake me!\n");
}
showPlate(head);
}
}
}
}
}
}</span>

程序某次运行部分结果如下：