用C语言模拟实现先来先服务、短作业优先、优先级和时间片轮转等操作系统中的进程调度算法。

好的，我可以为您解答这个问题。

首先，需要明确一下进程调度算法的概念。进程调度算法是操作系统用来决定哪个进程可以获得 CPU 时间片的一种策略。常见的调度算法有先来先服务、短作业优先、优先级和时间片轮转等。

下面，我将分别介绍这些调度算法在 C 语言中的模拟实现。

1. 先来先服务调度算法

先来先服务调度算法是最简单的调度算法，它按照进程到达的先后顺序进行调度。实现该算法的代码如下：

#include <stdio.h>

int main() {
    int n, i, j;
    float bt[20], wt[20], tat[20], avwt = 0, avtat = 0;

    printf("Enter the number of processes: ");
    scanf("%d", &n);

    printf("Enter the burst time for each process:\n");
    for(i = 0; i < n; i++) {
        printf("Process %d: ", i + 1);
        scanf("%f", &bt[i]);
    }

    wt[0] = 0;
    for(i = 1; i < n; i++) {
        wt[i] = 0;
        for(j = 0; j < i; j++)
            wt[i] += bt[j];
    }

    printf("\nProcess\t  Burst Time\t  Waiting Time\t  Turnaround Time");

    for(i = 0; i < n; i++) {
        tat[i] = bt[i] + wt[i];
        avwt += wt[i];
        avtat += tat[i];
        printf("\n   %d\t\t%5.2f\t\t%5.2f\t\t%5.2f", i + 1, bt[i], wt[i], tat[i]);
    }

    avwt /= i;
    avtat /= i;
    printf("\n\nAverage Waiting Time: %5.2f", avwt);
    printf("\nAverage Turnaround Time: %5.2f", avtat);

    return 0;
}

2. 短作业优先调度算法

短作业优先调度算法是按照进程的执行时间长短来进行调度的。实现该算法的代码如下：

#include <stdio.h>

int main() {
    int n, i, j, pos, temp;
    float bt[20], wt[20], tat[20], avwt = 0, avtat = 0;

    printf("Enter the number of processes: ");
    scanf("%d", &n);

    printf("Enter the burst time for each process:\n");
    for(i = 0; i < n; i++) {
        printf("Process %d: ", i + 1);
        scanf("%f", &bt[i]);
    }

    for(i = 0; i < n; i++) {
        pos = i;
        for(j = i + 1; j < n; j++) {
            if(bt[j] < bt[pos])
                pos = j;
        }

        temp = bt[i];
        bt[i] = bt[pos];
        bt[pos] = temp;
    }

    wt[0] = 0;
    for(i = 1; i < n; i++) {
        wt[i] = 0;
        for(j = 0; j < i; j++)
            wt[i] += bt[j];
    }

    printf("\nProcess\t  Burst Time\t  Waiting Time\t  Turnaround Time");

    for(i = 0; i < n; i++) {
        tat[i] = bt[i] + wt[i];
        avwt += wt[i];
        avtat += tat[i];
        printf("\n   %d\t\t%5.2f\t\t%5.2f\t\t%5.2f", i + 1, bt[i], wt[i], tat[i]);
    }

    avwt /= i;
    avtat /= i;
    printf("\n\nAverage Waiting Time: %5.2f", avwt);
    printf("\nAverage Turnaround Time: %5.2f", avtat);

    return 0;
}

3. 优先级调度算法

优先级调度算法是按照进程的优先级来进行调度的。实现该算法的代码如下：

#include <stdio.h>

int main() {
    int n, i, j, pos, temp, priority[20];
    float bt[20], wt[20], tat[20], avwt = 0, avtat = 0;

    printf("Enter the number of processes: ");
    scanf("%d", &n);

    printf("Enter the burst time and priority for each process:\n");
    for(i = 0; i < n; i++) {
        printf("Process %d: ", i + 1);
        scanf("%f %d", &bt[i], &priority[i]);
    }

    for(i = 0; i < n; i++) {
        pos = i;
        for(j = i + 1; j < n; j++) {
            if(priority[j] < priority[pos])
                pos = j;
        }

        temp = priority[i];
        priority[i] = priority[pos];
        priority[pos] = temp;

        temp = bt[i];
        bt[i] = bt[pos];
        bt[pos] = temp;
    }

    wt[0] = 0;
    for(i = 1; i < n; i++) {
        wt[i] = 0;
        for(j = 0; j < i; j++)
            wt[i] += bt[j];
    }

    printf("\nProcess\t  Burst Time\t  Waiting Time\t  Turnaround Time");

    for(i = 0; i < n; i++) {
        tat[i] = bt[i] + wt[i];
        avwt += wt[i];
        avtat += tat[i];
        printf("\n   %d\t\t%5.2f\t\t%5.2f\t\t%5.2f", i + 1, bt[i], wt[i], tat[i]);
    }

    avwt /= i;
    avtat /= i;
    printf("\n\nAverage Waiting Time: %5.2f", avwt);
    printf("\nAverage Turnaround Time: %5.2f", avtat);

    return 0;
}

4. 时间片轮转调度算法

时间片轮转调度算法是按照时间片的大小来分配 CPU 时间的。实现该算法的代码如下：

#include <stdio.h>

int main() {
    int n, i, j, time_quantum;
    float bt[20], rem_bt[20], wt[20], tat[20], avwt = 0, avtat = 0;

    printf("Enter the number of processes: ");
    scanf("%d", &n);

    printf("Enter the burst time for each process:\n");
    for(i = 0; i < n; i++) {
        printf("Process %d: ", i + 1);
        scanf("%f", &bt[i]);
        rem_bt[i] = bt[i];
    }

    printf("Enter the time quantum: ");
    scanf("%d", &time_quantum);

    int t = 0;
    while(1) {
        int done = 1;
        for(i = 0; i < n; i++) {
            if(rem_bt[i] > 0) {
                done = 0;
                if(rem_bt[i] > time_quantum) {
                    t += time_quantum;
                    rem_bt[i] -= time_quantum;
                } else {
                    t += rem_bt[i];
                    wt[i] = t - bt[i];
                    rem_bt[i] = 0;
                }
            }
        }
        if(done == 1) break;
    }

    for(i = 0; i < n; i++) {
        tat[i] = bt[i] + wt[i];
        avwt += wt[i];
        avtat += tat[i];
    }

    avwt /= i;
    avtat /= i;
    printf("\n\nAverage Waiting Time: %5.2f", avwt);
    printf("\nAverage Turnaround Time: %5.2f", avtat);

    return 0;
}

以上就是 C 语言模拟实现先来先服务、短作业优先、优先级和时间片轮转等操作系统中的进程调度算法的代码实现。