进程调度算法模拟程序代码

以下是一个简单的进程调度算法模拟程序代码，使用了先来先服务（FCFS）和短作业优先（SJF）两种调度算法。程序使用 C 语言编写。

#include <stdio.h>

struct process {
    int pid;        // 进程 ID
    int arrival;    // 到达时间
    int burst;      // 执行时间
    int wait;       // 等待时间
    int turnaround; // 周转时间
};

void fcfs(struct process* p, int n);
void sjf(struct process* p, int n);

int main() {
    struct process p[] = {
        {1, 0, 8, 0, 0},
        {2, 1, 4, 0, 0},
        {3, 2, 9, 0, 0},
        {4, 3, 5, 0, 0},
        {5, 4, 2, 0, 0},
    };
    int n = sizeof(p) / sizeof(struct process);

    fcfs(p, n);
    sjf(p, n);

    return 0;
}

void fcfs(struct process* p, int n) {
    printf("FCFS Algorithm:\n");

    int time = 0;
    float avg_wait = 0, avg_turnaround = 0;

    for (int i = 0; i < n; i++) {
        if (time < p[i].arrival) {
            time = p[i].arrival;
        }
        p[i].wait = time - p[i].arrival;
        p[i].turnaround = p[i].burst + p[i].wait;
        time += p[i].burst;

        printf("P%d: wait=%d, turnaround=%d\n", p[i].pid, p[i].wait, p[i].turnaround);

        avg_wait += p[i].wait;
        avg_turnaround += p[i].turnaround;
    }

    avg_wait /= n;
    avg_turnaround /= n;

    printf("Average Wait Time: %.2f\n", avg_wait);
    printf("Average Turnaround Time: %.2f\n", avg_turnaround);
}

void sjf(struct process* p, int n) {
    printf("SJF Algorithm:\n");

    int time = 0, done = 0;
    float avg_wait = 0, avg_turnaround = 0;

    while (done < n) {
        int shortest = -1;
        for (int i = 0; i < n; i++) {
            if (p[i].arrival <= time && p[i].burst > 0) {
                if (shortest == -1 || p[i].burst < p[shortest].burst) {
                    shortest = i;
                }
            }
        }

        if (shortest == -1) {
            time++;
            continue;
        }

        p[shortest].wait = time - p[shortest].arrival;
        p[shortest].turnaround = p[shortest].burst + p[shortest].wait;
        time += p[shortest].burst;
        p[shortest].burst = 0;
        done++;

        printf("P%d: wait=%d, turnaround=%d\n", p[shortest].pid, p[shortest].wait, p[shortest].turnaround);

        avg_wait += p[shortest].wait;
        avg_turnaround += p[shortest].turnaround;
    }

    avg_wait /= n;
    avg_turnaround /= n;

    printf("Average Wait Time: %.2f\n", avg_wait);
    printf("Average Turnaround Time: %.2f\n", avg_turnaround);
}

该程序使用了一个 `struct` 结构体来表示每个进程的信息，包括进程 ID、到达时间、执行时间、等待时间和周转时间。`fcfs()` 函数使用先来先服务算法计算等待时间和周转时间，并输出每个进程的信息和平均等待时间和平均周转时间。`sjf()` 函数使用短作业优先算法计算等待时间和周转时间，并输出每个进程的信息和平均等待时间和平均周转时间。程序中的进程信息是硬编码的，实际应用中应该从文件或用户输入中读取。