银行家算法实现

银行家算法实现

两天写完的，更改痕迹还没删，可能不是很严谨，有不足的地方欢迎更正。

#define _CRT_SECURE_NO_WARNINGS
#include <iostream> 
#define N 10

#define LEN sizeof(PCB)

/*typedef struct Ziyuan
{
	int a[N];
	int b;
}Zy;*/

/*typedef struct Juzhen
{
	Zy max;//最大资源
	Zy allocation;//已分配
	Zy need;
}Jz;*/
int z = 3;
int m = 5;
int available[N];
int request[N];
int copy[N];
int copy2[N];
typedef struct PCB
{
	char name;
	int max[N];//最大资源
	int allocation[N];//已分配
	int need[N];
	int biaoji;//完成标记
	struct PCB* up;
	struct PCB* next;
}PCB;
PCB* safe[N];
PCB* creat() {
	m = 0;
	char name;
	char k = '0';
	int alloction,need;
	PCB* head, *p1, *p2;
	head = p1 = p2 = NULL;
	head = (PCB*)malloc(LEN);
	if (head)head->next = NULL;
	p2 = head;
	while (true) {
		//int lei = 1;
		printf("进程名(输入0结束):");
		scanf_s("%c", &name, sizeof(name));
		if (name == k) {
			break;
		}else {
			p1 = (PCB*)malloc(LEN);
			if(p1)p1->name = name;
			if(p1)p1->biaoji = 0;
			m++;//进程个数
			printf("\nallocation\n");
			for (int i = 0; i < z; i++) {
				printf("第%d类资源:", i + 1);
				scanf_s("%d", &alloction);
				p1->allocation[i] = alloction;
			}
			printf("need\n");
			for (int i = 0; i < z; i++) {
				printf("第%d类资源:", i + 1);
				scanf_s("%d", &need);
				p1->need[i] = need;
			}
			getchar();
			if (p2)p2->next = p1;
			if (p1)p1->up = p2;
			if (p1)p1->next = NULL;
			p2 = p1;
		}
	}
	return head;
}
/*void cp1() {//备份更改后
	for (size_t i = 0; i < z; i++)
	{
		copy[i] = available[i];
	}
}
void cp2() {//备份更改前
	for (size_t i = 0; i < z; i++)
	{
		copy2[i] = available[i];
	}
}
void hf1() {//恢复更改后
	for (size_t i = 0; i < z; i++)
	{
		available[i] = copy[i];
	}
}
void hf2() {//恢复更改前
	for (size_t i = 0; i < z; i++)
	{
		available[i] = copy2[i];
	}
}*/
void hhh() {
	printf("*******\navailable：");
	for (size_t i = 0; i < z; i++)
	{
		printf("%d  ",available[i]);
	}
	printf("\n");
}
void xs(PCB* tou) {
	PCB* u, * n;
	u = tou;
	n = tou->next;
	printf("进程\talloction\tneed\n");
	while (n) {
		printf("%c\t", n->name);
		for (size_t i = 0; i < z; i++)//unsigned int
		{
			printf("%d  ",n->allocation[i]);
		}
		printf("\t");
		for (size_t i = 0; i < z; i++)
		{
			printf("%d ", n->need[i]);
		}
		printf("\n");
		n = n->next;
	}
}
PCB* cx(PCB* tou,char x) {
	PCB* p = tou;
	int i = 0;
	if (p) {
		p = tou->next;
		while (p)
		{
			if (p->name == x) {
				printf("已找到该进程:%c\n",p->name);
				i = 1;
				break;
			}
			p = p->next;
		}
	}
	if (i == 1) {
		return p;
	}
	else {
		printf("未找到进程\n");
		return NULL;
	}
}
void huisu(PCB* tou,PCB *k){
	int b = 0;
	int wanchen = 0;
	PCB* qq = k;
	PCB* l = tou->next;
	for (size_t i = 0; i < z; i++)
	{
		if (request[i] > qq->need[i])b = 1;//请求大于需求
		if (request[i] > available[i])b = 2;//请求大于系统空闲
	}
//	cp2();
	if (b == 0) {
		printf("试分配成功，正在寻找安全序列......\n");
		for (size_t i = 0; i < z; i++)
		{
			k->allocation[i] = k->allocation[i] + request[i];
			k->need[i] = k->need[i] - request[i];
			available[i] = available[i] - request[i];
		}
//		cp1();//备份更改后
		while (l)
		{
			if (l->biaoji == 0) {//未完成进程才比较资源
				int leijia = 0;
				for (size_t i = 0; i < z; i++)
				{
					if (available[i] >= l->need[i])leijia++;
				}
				if (leijia == 3)
				{
					for (size_t i = 0; i < z; i++)
					{
						available[i] = available[i] + l->allocation[i];//完成进程并回收已分配的程序
					}
					l->biaoji = 1;
					safe[wanchen] = l;
					wanchen++;
					l = tou;
				}
			}
			l = l->next;
		}
	}
	if (wanchen != m) {//没有都完成
		for (int i = wanchen - 1; i >= 0; i--)
		{
			for (size_t j = 0; j < z; j++)
			{
				available[j] = available[j] - safe[i]->allocation[j];
				printf("1");
			}
		}
		if (b == 0) {
			for (size_t i = 0; i < z; i++)
			{
				k->allocation[i] = k->allocation[i] - request[i];
				k->need[i] = k->need[i] + request[i];
				available[i] = available[i] + request[i];
			}
		}
//		hhh();
//		hf2();
		printf("寻找安全序列失败，已回溯到请求前\n");
		hhh();//显示当前空闲资源
	}
	else
	{
		printf("分配成功！\n安全序列为：");
		for (size_t i = 0; i < m; i++)
		{
			printf("%c",safe[i]->name);
		}
//		hf1();//恢复
		printf("\n");
		hhh();
	}
}

int main() {
	PCB* h = NULL;
	PCB* chax = NULL;
	char jc;
	printf("资源个数：");
	scanf_s("%d",&z);
	getchar();
	h = creat();
	xs(h);
	printf("当前系统空闲资源：\n");
	for (size_t i = 0; i < z; i++)
	{
		printf("第%d类资源:", i + 1);
		scanf("%d",&available[i]);
	}
	while (true)
	{		
		getchar();
		printf("需要请求资源的进程名:(0结束)");
		scanf_s("%c", &jc, sizeof(jc));
		if (jc == '0')break;
		chax = cx(h, jc);
		//while (chax){	}
		if (chax) {
			printf("增量请求资源:");
			for (size_t i = 0; i < z; i++)
			{
				printf("第%d类资源:", i + 1);
				scanf("%d", &request[i]);
			}
			huisu(h, chax);
			xs(h);
		}
		else
		{
			printf("11111111");
			xs(h);
		}
	}
}```

来源：CSDN

作者：Mr.星空

链接：https://blog.csdn.net/A1669898261/article/details/103482970