编写C程序，模拟“最短作业优先（SJF）” 调度算法，编写以下函数，计算平均带权周转时间并返回，空函数： double sjf_weighted_time (int *arrival_time, int *run_time, int num){ }，主函数int job_num = 5;//job number int arrival_time[] = { 0, 1, 2, 5, 7 };//arrival time int run_time[] = { 8, 2, 3, 10, 9 };//run time //SJF double result = sjf_weighted_time(arrival_time, run_time, job_num); printf("%.2lf", result);

以下是实现最短作业优先（SJF）算法计算平均带权周转时间的 C 语言代码：

#include <stdio.h>

double sjf_weighted_time(int *arrival_time, int *run_time, int num) {
    double completion_time[num], turn_around_time[num], waiting_time[num], total_waiting_time = 0, total_turn_around_time = 0;

    // 完成时间初始化为0
    for (int i = 0; i < num; i++) {
        completion_time[i] = 0;
    }

    // 按到达时间排序作业
    for (int i = 0; i < num; i++) {
        for (int j = i + 1; j < num; j++) {
            if (arrival_time[i] > arrival_time[j]) {
                int temp = arrival_time[i];
                arrival_time[i] = arrival_time[j];
                arrival_time[j] = temp;
                temp = run_time[i];
                run_time[i] = run_time[j];
                run_time[j] = temp;
            }
        }
    }

    // 计算完成时间和周转时间
    for (int i = 0; i < num; i++) {
        if (i == 0) {
            completion_time[i] = arrival_time[i] + run_time[i];
        } else {
            if (arrival_time[i] > completion_time[i - 1]) {
                completion_time[i] = arrival_time[i] + run_time[i];
            } else {
                completion_time[i] = completion_time[i - 1] + run_time[i];
            }
        }
        turn_around_time[i] = completion_time[i] - arrival_time[i];
    }

    // 计算带权周转时间和平均带权周转时间
    for (int i = 0; i < num; i++) {
        waiting_time[i] = turn_around_time[i] - run_time[i];
        total_waiting_time += waiting_time[i];
        total_turn_around_time += turn_around_time[i];
    }

    return total_turn_around_time / num / run_time[0];
}

int main() {
    int job_num = 5;
    int arrival_time[] = {0, 1, 2, 5, 7};
    int run_time[] = {8, 2, 3, 10, 9};
    double result = sjf_weighted_time(arrival_time, run_time, job_num);
    printf("平均带权周转时间为：%.2lf", result);
    return 0;
}

该程序实现了最短作业优先（SJF）算法计算平均带权周转时间的功能。主函数中定义了作业数、到达时间数组和运行时间数组，然后调用 `sjf_weighted_time` 函数计算平均带权周转时间，并输出结果。