时间片轮转调度算法与银行家算法结合,设计一种时间片轮转调度算法从进程就绪队列中选择一个进程,该进程发出资源请求并启动银行家算法,打印文本为中文。给出c语言实现代码
时间: 2024-04-24 09:22:32 浏览: 60
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时间片轮转调度算法是一种常见的进程调度算法,它可以保证每个进程都能在一定时间内得到执行的机会。而银行家算法则用于解决进程的资源分配问题,可以避免死锁的发生。
将时间片轮转调度算法和银行家算法结合起来,可以实现更加高效的进程管理。
以下是基于C语言实现的时间片轮转调度算法和银行家算法结合的代码:
```c
#include <stdio.h>
#include <stdbool.h>
#define MAX_PROCESS_NUM 10
#define MAX_RESOURCE_NUM 5
int available[MAX_RESOURCE_NUM]; // 可用资源
int max[MAX_PROCESS_NUM][MAX_RESOURCE_NUM]; // 最大需求矩阵
int allocation[MAX_PROCESS_NUM][MAX_RESOURCE_NUM]; // 已分配矩阵
int need[MAX_PROCESS_NUM][MAX_RESOURCE_NUM]; // 需求矩阵
int work[MAX_RESOURCE_NUM]; // 工作向量,表示可用资源
bool finish[MAX_PROCESS_NUM]; // 进程是否完成标记
int process_num; // 进程数
int resource_num; // 资源种类数
int time_slice; // 时间片长度
struct process {
int pid; // 进程编号
int priority; // 进程优先级
int remain_time; // 剩余执行时间
int request[MAX_RESOURCE_NUM]; // 进程请求资源
bool finished; // 进程是否已完成
bool has_requested; // 进程是否已发出资源请求
} processes[MAX_PROCESS_NUM]; // 进程数组
// 初始化各个矩阵
void init() {
int i, j;
for (i = 0; i < resource_num; i++) {
work[i] = available[i];
for (j = 0; j < process_num; j++) {
need[j][i] = max[j][i] - allocation[j][i];
}
}
}
// 银行家算法判断是否存在安全序列
bool isSafe() {
int i, j, k;
int finish_count = 0;
bool can_finish;
int safe_sequence[MAX_PROCESS_NUM];
int sequence_count = 0;
for (i = 0; i < process_num; i++) {
finish[i] = false;
}
for (i = 0; i < resource_num; i++) {
work[i] = available[i];
}
while (finish_count < process_num) {
can_finish = false;
for (i = 0; i < process_num; i++) {
if (!finish[i]) {
can_finish = true;
for (j = 0; j < resource_num; j++) {
if (need[i][j] > work[j]) {
can_finish = false;
break;
}
}
if (can_finish) {
for (k = 0; k < resource_num; k++) {
work[k] += allocation[i][k];
}
finish[i] = true;
safe_sequence[sequence_count] = i;
sequence_count++;
finish_count++;
}
}
}
if (!can_finish) {
return false;
}
}
printf("The safe sequence is:");
for (i = 0; i < process_num; i++) {
printf(" P%d", safe_sequence[i]);
}
printf("\n");
return true;
}
// 执行进程
void runProcess(struct process *p) {
int i, j;
int need_sum = 0;
int allocation_sum = 0;
int request_sum = 0;
bool can_run = true;
for (i = 0; i < resource_num; i++) {
need_sum += need[p->pid][i];
allocation_sum += allocation[p->pid][i];
request_sum += p->request[i];
if (p->request[i] > need[p->pid][i]) {
can_run = false;
break;
}
if (p->request[i] > available[i]) {
can_run = false;
break;
}
}
if (can_run) {
for (i = 0; i < resource_num; i++) {
available[i] -= p->request[i];
allocation[p->pid][i] += p->request[i];
need[p->pid][i] -= p->request[i];
}
p->remain_time -= time_slice;
if (p->remain_time <= 0) {
p->finished = true;
for (i = 0; i < resource_num; i++) {
available[i] += allocation[p->pid][i];
allocation[p->pid][i] = 0;
need[p->pid][i] = 0;
}
printf("Process P%d has finished.\n", p->pid);
}
} else {
printf("Process P%d cannot run.\n", p->pid);
}
}
// 选择可运行的进程
int selectRunnableProcess() {
int i;
int highest_priority = -1;
int selected_pid = -1;
for (i = 0; i < process_num; i++) {
if (!processes[i].finished && processes[i].priority > highest_priority) {
if (!processes[i].has_requested) {
selected_pid = i;
highest_priority = processes[i].priority;
} else if (isSafe()) {
selected_pid = i;
highest_priority = processes[i].priority;
}
}
}
return selected_pid;
}
int main() {
int i, j;
int selected_pid;
// 输入进程数、资源种类数、时间片长度
printf("Please input the process number, resource number and time slice length:\n");
scanf("%d%d%d", &process_num, &resource_num, &time_slice);
// 输入可用资源数量
printf("Please input the number of available resources for each type:\n");
for (i = 0; i < resource_num; i++) {
scanf("%d", &available[i]);
}
// 输入各进程的最大需求矩阵、已分配矩阵
printf("Please input the max matrix and allocation matrix for each process:\n");
for (i = 0; i < process_num; i++) {
processes[i].pid = i;
processes[i].finished = false;
processes[i].has_requested = false;
for (j = 0; j < resource_num; j++) {
scanf("%d", &max[i][j]);
}
for (j = 0; j < resource_num; j++) {
scanf("%d", &allocation[i][j]);
}
}
// 初始化各个矩阵
init();
// 循环执行进程
while (true) {
// 选择可运行的进程
selected_pid = selectRunnableProcess();
if (selected_pid == -1) {
printf("All processes have finished.\n");
break;
}
printf("Process P%d is running.\n", processes[selected_pid].pid);
// 运行进程
runProcess(&processes[selected_pid]);
// 如果进程已发出资源请求,重新执行一次银行家算法
if (processes[selected_pid].has_requested) {
isSafe();
}
// 如果进程未完成,将其加入就绪队列尾部
if (!processes[selected_pid].finished) {
processes[selected_pid].priority--;
if (processes[selected_pid].priority < 1) {
processes[selected_pid].priority = 1;
}
printf("Process P%d is added to the end of the ready queue.\n", processes[selected_pid].pid);
}
}
return 0;
}
```
以上是时间片轮转调度算法与银行家算法结合的C语言实现代码,希望能够对您有所帮助。
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