银行家算法避免死锁的代码
时间: 2023-11-22 22:50:21 浏览: 61
银行家算法是一种用于避免死锁的算法。它通过动态地分配资源来确保系统的安全性。以下是一个简单的银行家算法避免死锁的代码示例:
```c
#include <stdio.h>
#define MAX_PROCESSES 10
#define MAX_RESOURCES 10
int available[MAX_RESOURCES];
int max[MAX_PROCESSES][MAX_RESOURCES];
int allocation[MAX_PROCESSES][MAX_RESOURCES];
int need[MAX_PROCESSES][MAX_RESOURCES];
int main() {
int num_processes, num_resources;
// 输入进程数和资源数
printf("Enter the number of processes: ");
scanf("%d", &num_processes);
printf("Enter the number of resources: ");
scanf("%d", &num_resources);
// 输入可用资源数
printf("Enter the available resources: ");
for (int i = 0; i < num_resources; i++) {
scanf("%d", &available[i]);
}
// 输入最大需求矩阵
printf("Enter the maximum demand matrix:\n");
for (int i = 0; i < num_processes; i++) {
for (int j = 0; j < num_resources; j++) {
scanf("%d", &max[i][j]);
}
}
// 输入分配矩阵
printf("Enter the allocation matrix:\n");
for (int i = 0; i < num_processes; i++) {
for (int j = 0; j < num_resources; j++) {
scanf("%d", &allocation[i][j]);
}
}
// 计算需求矩阵
for (int i = 0; i < num_processes; i++) {
for (int j = 0; j < num_resources; j++) {
need[i][j] = max[i][j] - allocation[i][j];
}
}
// 银行家算法避免死锁
int work[MAX_RESOURCES];
int finish[MAX_PROCESSES] = {0};
int safe_sequence[MAX_PROCESSES];
int count = 0;
for (int i = 0; i < num_resources; i++) {
work[i] = available[i];
}
while (count < num_processes) {
int found = 0;
for (int i = 0; i < num_processes; i++) {
if (finish[i] == 0) {
int j;
for (j = 0; j < num_resources; j++) {
if (need[i][j] > work[j]) {
break;
}
}
if (j == num_resources) {
for (int k = 0; k < num_resources; k++) {
work[k] += allocation[i][k];
}
safe_sequence[count++] = i;
finish[i] = 1;
found = 1;
}
}
}
if (found == 0) {
break;
}
}
// 输出安全序列
if (count == num_processes) {
printf("Safe sequence: ");
for (int i = 0; i < num_processes; i++) {
printf("%d ", safe_sequence[i]);
}
printf("\n");
} else {
printf("Unsafe state\n");
}
return 0;
}
```
这段代码实现了银行家算法的避免死锁部分。它首先输入进程数、资源数、可用资源数、最大需求矩阵和分配矩阵。然后,它计算需求矩阵,并使用银行家算法判断系统是否处于安全状态。如果是安全状态,则输出安全序列;否则,输出不安全状态。