用一个C语言模拟代码实现PSA（优先级）和RR（时间片轮转）操作系统

PSA优先级调度算法的C语言实现：

#include <stdio.h>

#define MAX_PROCESS 10

struct Process {
    int id;
    int priority;
    int burst_time;
    int arrival_time;
    int waiting_time;
    int turnaround_time;
};

int main() {
    int n, i, j, total_waiting_time = 0, total_turnaround_time = 0;
    float avg_waiting_time, avg_turnaround_time;
    struct Process p[MAX_PROCESS], temp;
    
    // 输入进程信息
    printf("请输入进程数量（最多%d个）：", MAX_PROCESS);
    scanf("%d", &n);
    printf("请依次输入每个进程的优先级、CPU执行时间和到达时间：\n");
    for (i = 0; i < n; i++) {
        p[i].id = i + 1;
        scanf("%d %d %d", &p[i].priority, &p[i].burst_time, &p[i].arrival_time);
    }
    
    // 按照优先级对进程进行排序
    for (i = 0; i < n - 1; i++) {
        for (j = 0; j < n - i - 1; j++) {
            if (p[j].priority < p[j + 1].priority) {
                temp = p[j];
                p[j] = p[j + 1];
                p[j + 1] = temp;
            }
        }
    }
    
    // 计算等待时间和周转时间
    for (i = 0; i < n; i++) {
        p[i].waiting_time = i == 0 ? 0 : p[i - 1].waiting_time + p[i - 1].burst_time;
        p[i].turnaround_time = p[i].waiting_time + p[i].burst_time;
        total_waiting_time += p[i].waiting_time;
        total_turnaround_time += p[i].turnaround_time;
    }
    
    // 输出结果
    printf("进程ID\t优先级\tCPU执行时间\t到达时间\t等待时间\t周转时间\n");
    for (i = 0; i < n; i++) {
        printf("%d\t%d\t%d\t\t%d\t\t%d\t\t%d\n", p[i].id, p[i].priority, p[i].burst_time, p[i].arrival_time, p[i].waiting_time, p[i].turnaround_time);
    }
    avg_waiting_time = (float) total_waiting_time / n;
    avg_turnaround_time = (float) total_turnaround_time / n;
    printf("平均等待时间：%.2f\n平均周转时间：%.2f\n", avg_waiting_time, avg_turnaround_time);
    
    return 0;
}

RR时间片轮转调度算法的C语言实现：

#include <stdio.h>

#define MAX_PROCESS 10

struct Process {
    int id;
    int burst_time;
    int arrival_time;
    int remaining_time;
    int waiting_time;
    int turnaround_time;
};

int main() {
    int n, i, j, time_quantum, total_waiting_time = 0, total_turnaround_time = 0;
    float avg_waiting_time, avg_turnaround_time;
    struct Process p[MAX_PROCESS], temp;
    
    // 输入进程信息
    printf("请输入进程数量（最多%d个）：", MAX_PROCESS);
    scanf("%d", &n);
    printf("请依次输入每个进程的CPU执行时间和到达时间：\n");
    for (i = 0; i < n; i++) {
        p[i].id = i + 1;
        scanf("%d %d", &p[i].burst_time, &p[i].arrival_time);
        p[i].remaining_time = p[i].burst_time;
    }
    printf("请输入时间片大小：");
    scanf("%d", &time_quantum);
    
    // 时间片轮转调度
    for (i = 0; ; i++) {
        int all_finished = 1; // 所有进程是否都已经完成
        for (j = 0; j < n; j++) {
            if (p[j].remaining_time > 0) {
                all_finished = 0;
                if (p[j].remaining_time > time_quantum) {
                    // 执行时间超过时间片大小
                    p[j].remaining_time -= time_quantum;
                    i += time_quantum - 1; // 时间片耗尽，更新时间
                } else {
                    // 执行时间不足时间片大小，执行完毕
                    p[j].waiting_time = i - p[j].arrival_time - p[j].burst_time + p[j].remaining_time;
                    p[j].remaining_time = 0;
                }
            }
        }
        if (all_finished) {
            break;
        }
    }
    
    // 计算周转时间
    for (i = 0; i < n; i++) {
        p[i].turnaround_time = p[i].burst_time + p[i].waiting_time;
        total_waiting_time += p[i].waiting_time;
        total_turnaround_time += p[i].turnaround_time;
    }
    
    // 输出结果
    printf("进程ID\tCPU执行时间\t到达时间\t等待时间\t周转时间\n");
    for (i = 0; i < n; i++) {
        printf("%d\t%d\t\t%d\t\t%d\t\t%d\n", p[i].id, p[i].burst_time, p[i].arrival_time, p[i].waiting_time, p[i].turnaround_time);
    }
    avg_waiting_time = (float) total_waiting_time / n;
    avg_turnaround_time = (float) total_turnaround_time / n;
    printf("平均等待时间：%.2f\n平均周转时间：%.2f\n", avg_waiting_time, avg_turnaround_time);
    
    return 0;
}