编写一段程序模拟银行家算法用c语言
时间: 2024-10-18 14:19:33 浏览: 70
银行家算法是一种资源分配策略,用于避免死锁,它通过动态调整进程的资源请求来确保系统的安全性。下面是一个简单的银行家算法的C语言实现示例,假设我们有三个类型的资源(R1、R2、R3),以及四个进程:
```c
#include <stdio.h>
// 定义全局变量
#define MAX_PROCESSES 4
#define MAX_RESOURCES 5
int resources[MAX_RESOURCES] = {0};
int process_requests[MAX_PROCESSES][MAX_RESOURCES] = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
int system_limits[MAX_RESOURCES];
int num_processes, available_resources;
void is_safe(int* requests, int* limits) {
int max_row = 0;
for (int i = 0; i < num_processes; i++) {
int row_sum = 0;
for (int j = 0; j < MAX_RESOURCES; j++) {
row_sum += requests[i][j];
}
if (row_sum > limits[max_row]) {
max_row = i;
}
}
// Check if there's enough available resources to grant the request
return available_resources >= (row_sum - limits[max_row]);
}
int main() {
// 初始化系统资源限制和进程需求
system_limits[0] = 3; // R1 limit
system_limits[1] = 2; // R2 limit
system_limits[2] = 4; // R3 limit
num_processes = 4;
available_resources = MAX_RESOURCES; // 假设所有资源一开始都有
printf("Enter process resource requests:\n");
for (int i = 0; i < num_processes; i++) {
for (int j = 0; j < MAX_RESOURCES; j++) {
scanf("%d", &process_requests[i][j]);
}
}
while (true) {
int safe = is_safe(process_requests, system_limits);
if (safe) {
// 如果安全,分配资源并更新可用资源
for (int i = 0; i < num_processes; i++) {
for (int j = 0; j < MAX_RESOURCES; j++) {
if (resources[j] < process_requests[i][j]) {
resources[j]++;
}
}
}
printf("Resources allocated.\n");
} else {
printf("Not safe to allocate resources, deadlock prevention.\n");
break;
}
}
return 0;
}
```
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