编写C程序,模拟实现单处理器系统中的进程调度算法,实现多个进程的模拟调度,要求采用见的进程调度算法(如先来先服务、时间片轮转、优先等级等调度算法)进行模拟。
时间: 2024-03-13 19:47:38 浏览: 84
好的,我可以帮你回答这个问题。
下面是一个使用时间片轮转算法模拟进程调度的C程序:
```c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define MAX_PROCESS_NUM 10 // 最大进程数
#define MAX_TIME_SLICE 4 // 时间片长度
struct Process {
int pid; // 进程ID
int arrival; // 到达时间
int burst; // 执行时间
int remaining; // 剩余执行时间
int finish; // 完成时间
int turnaround; // 周转时间
int waiting; // 等待时间
};
struct ProcessQueue {
struct Process *processes[MAX_PROCESS_NUM]; // 进程队列
int front; // 队首指针
int rear; // 队尾指针
};
struct Process *create_process(int pid, int arrival, int burst);
void destroy_process(struct Process *process);
void enqueue(struct ProcessQueue *queue, struct Process *process);
struct Process *dequeue(struct ProcessQueue *queue);
int is_empty(struct ProcessQueue *queue);
void print_queue(struct ProcessQueue *queue);
void run_scheduler(struct ProcessQueue *queue);
void print_statistics(struct ProcessQueue *queue);
int main(int argc, char **argv)
{
// 初始化进程队列
struct ProcessQueue queue = { .front = 0, .rear = -1 };
// 创建进程并加入队列
struct Process *p1 = create_process(1, 0, 6);
enqueue(&queue, p1);
struct Process *p2 = create_process(2, 1, 8);
enqueue(&queue, p2);
struct Process *p3 = create_process(3, 2, 7);
enqueue(&queue, p3);
struct Process *p4 = create_process(4, 3, 3);
enqueue(&queue, p4);
struct Process *p5 = create_process(5, 4, 4);
enqueue(&queue, p5);
// 运行调度器并打印统计信息
run_scheduler(&queue);
print_statistics(&queue);
// 销毁进程和进程队列
destroy_process(p1);
destroy_process(p2);
destroy_process(p3);
destroy_process(p4);
destroy_process(p5);
return 0;
}
struct Process *create_process(int pid, int arrival, int burst)
{
struct Process *process = (struct Process *)malloc(sizeof(struct Process));
process->pid = pid;
process->arrival = arrival;
process->burst = burst;
process->remaining = burst;
process->finish = 0;
process->turnaround = 0;
process->waiting = 0;
return process;
}
void destroy_process(struct Process *process)
{
free(process);
}
void enqueue(struct ProcessQueue *queue, struct Process *process)
{
if (queue->rear == MAX_PROCESS_NUM - 1) {
printf("Error: the process queue is full\n");
exit(1);
}
queue->rear++;
queue->processes[queue->rear] = process;
}
struct Process *dequeue(struct ProcessQueue *queue)
{
if (is_empty(queue)) {
printf("Error: the process queue is empty\n");
exit(1);
}
struct Process *process = queue->processes[queue->front];
queue->front++;
return process;
}
int is_empty(struct ProcessQueue *queue)
{
return queue->rear < queue->front;
}
void print_queue(struct ProcessQueue *queue)
{
printf("Process Queue:\n");
for (int i = queue->front; i <= queue->rear; i++) {
printf(" pid=%d arrival=%d burst=%d remaining=%d\n",
queue->processes[i]->pid, queue->processes[i]->arrival,
queue->processes[i]->burst, queue->processes[i]->remaining);
}
}
void run_scheduler(struct ProcessQueue *queue)
{
int time = 0;
while (!is_empty(queue)) {
// 从队列中取出一个进程
struct Process *process = dequeue(queue);
// 执行时间片
int slice = process->remaining > MAX_TIME_SLICE ? MAX_TIME_SLICE : process->remaining;
process->remaining -= slice;
// 更新进程的等待时间和周转时间
process->waiting += time - process->finish;
time += slice;
if (process->remaining == 0) {
process->finish = time;
process->turnaround = process->finish - process->arrival;
} else {
enqueue(queue, process);
}
}
}
void print_statistics(struct ProcessQueue *queue)
{
int total_turnaround = 0;
int total_waiting = 0;
printf("Process Statistics:\n");
for (int i = queue->front; i <= queue->rear; i++) {
printf(" pid=%d finish=%d turnaround=%d waiting=%d\n",
queue->processes[i]->pid, queue->processes[i]->finish,
queue->processes[i]->turnaround, queue->processes[i]->waiting);
total_turnaround += queue->processes[i]->turnaround;
total_waiting += queue->processes[i]->waiting;
}
printf("Average turnaround time: %.2f\n", (double)total_turnaround / (queue->rear - queue->front + 1));
printf("Average waiting time: %.2f\n", (double)total_waiting / (queue->rear - queue->front + 1));
}
```
在这个程序中,我们使用了一个结构体来表示进程,包括进程ID、到达时间、执行时间、剩余执行时间、完成时间、周转时间和等待时间。我们还使用了一个结构体来表示进程队列,其中包含一个指向进程数组的指针、一个队首指针和一个队尾指针。
在主函数中,我们首先创建了五个进程并加入进程队列中。然后,我们运行了时间片轮转算法的调度器,并打印了统计信息。最后,我们销毁了进程和进程队列。
在调度器函数中,我们从队列中取出一个进程,执行一个时间片,并更新进程的剩余执行时间、等待时间和周转时间。如果进程的剩余执行时间为0,则说明进程已经完成,更新进程的完成时间,并计算进程的周转时间。否则,我们将进程重新加入队列中。
在打印统计信息函数中,我们打印了每个进程的完成时间、周转时间和等待时间,并计算了平均周转时间和平均等待时间。
注意:这里只是一个简单的示例,实际的进程调度算法可能会更加复杂。
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