避免死锁银行家算法c++
时间: 2023-10-18 17:31:59 浏览: 63
在C语言中实现避免死锁的银行家算法可以通过以下步骤来实现:
1. 定义资源的最大需求量、已分配数量和可用资源数量。
```c
int max[NUMBER_OF_CUSTOMERS][NUMBER_OF_RESOURCES];
int allocation[NUMBER_OF_CUSTOMERS][NUMBER_OF_RESOURCES];
int available[NUMBER_OF_RESOURCES];
```
2. 实现安全性检查函数,判断当前状态是否安全。
```c
int isSafeState(int customer_id, int request[]) {
// 模拟分配资源给该进程
for (int i = 0; i < NUMBER_OF_RESOURCES; i++) {
available[i] -= request[i];
allocation[customer_id][i] += request[i];
}
// 执行安全性检查
int work[NUMBER_OF_RESOURCES];
bool finish[NUMBER_OF_CUSTOMERS]; for (int i = 0; i < NUMBER_OF_RESOURCES; i++) {
work[i] = available[i];
}
memset(finish, false, sizeof(finish));
int count = 0;
while (count < NUMBER_OF_CUSTOMERS) {
bool found = false;
for (int i = 0; i < NUMBER_OF_CUSTOMERS; i++) {
if (!finish[i]) {
bool canFinish = true;
for (int j = 0; j < NUMBER_OF_RESOURCES; j++) {
if (max[i][j] - allocation[i][j] > work[j]) {
canFinish = false;
break;
}
}
if (canFinish) {
// 进程可以完成,释放资源
finish[i] = true;
for (int j = 0; j < NUMBER_OF_RESOURCES; j++) {
work[j] += allocation[i][j];
}
found = true;
count++;
}
}
}
if (!found) {
// 没有找到可完成的进程
break;
}
}
// 恢复分配资源前的状态
for (int i = 0; i < NUMBER_OF_RESOURCES; i++) {
available[i] += request[i];
allocation[customer_id][i] -= request[i];
}
return count == NUMBER_OF_CUSTOMERS;
}
```
3. 实现资源请求函数,处理进程对资源的请求。
```c
bool requestResources(int customer_id, int request[]) {
// 检查请求是否超过最大需求量
for (int i = 0; i < NUMBER_OF_RESOURCES; i++) {
if (request[i] > max[customer_id][i] - allocation[customer_id][i]) {
return false;
}
}
// 检查请求是否超过可用资源数量
for (int i = 0; i < NUMBER_OF_RESOURCES; i++) {
if (request[i] > available[i]) {
return false;
}
}
// 检查安全性并分配资源
if (isSafeState(customer_id, request)) {
for (int i = 0; i < NUMBER_OF_RESOURCES; i++) {
available[i] -= request[i];
allocation[customer_id][i] += request[i];
}
return true;
} else {
return false;
}
}
```
这样就可以通过调用`requestResources`函数来处理进程对资源的请求,并且使用`isSafeState`函数来判断当前状态是否安全。注意,上述代码只是一个简单的示例,实际应用中可能需要根据具体情况进行修改和完善。