处理机调度c语言

处理机调度是操作系统中的一个重要功能，其作用是决定在何时执行哪个进程。C语言可以用来实现处理机调度算法。以下是一个简单的处理机调度程序实现，使用了Round Robin算法。

#include <stdio.h>
#include <stdlib.h>

#define MAX 1000

struct Process {
    int pid;
    int burst_time;
    int remaining_time;
    int arrival_time;
};

int main() {
    int n, quantum_time;
    struct Process p[MAX];
    int waiting_time[MAX], turnaround_time[MAX];
    int total_waiting_time = 0, total_turnaround_time = 0, total_burst_time = 0;
    int i, j, time = 0;

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

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

    for(i = 0; i < n; i++) {
        p[i].pid = i+1;
        printf("Enter burst time for process %d: ", i+1);
        scanf("%d", &p[i].burst_time);
        p[i].remaining_time = p[i].burst_time;
        printf("Enter arrival time for process %d: ", i+1);
        scanf("%d", &p[i].arrival_time);
        total_burst_time += p[i].burst_time;
    }

    while(total_burst_time > 0) {
        for(i = 0; i < n; i++) {
            if(p[i].remaining_time == 0) continue;
            if(p[i].remaining_time > quantum_time) {
                p[i].remaining_time -= quantum_time;
                total_burst_time -= quantum_time;
                time += quantum_time;
            } else {
                total_burst_time -= p[i].remaining_time;
                time += p[i].remaining_time;
                p[i].remaining_time = 0;
                turnaround_time[i] = time - p[i].arrival_time;
                waiting_time[i] = turnaround_time[i] - p[i].burst_time;
                total_waiting_time += waiting_time[i];
                total_turnaround_time += turnaround_time[i];
            }
        }
    }

    printf("\nPID\tBurst Time\tArrival Time\tWaiting Time\tTurnaround Time\n");
    for(i = 0; i < n; i++) {
        printf("%d\t%d\t\t%d\t\t%d\t\t%d\n", p[i].pid, p[i].burst_time, p[i].arrival_time, waiting_time[i], turnaround_time[i]);
    }

    printf("\nAverage waiting time: %.2f", (float)total_waiting_time/n);
    printf("\nAverage turnaround time: %.2f", (float)total_turnaround_time/n);

    return 0;
}

在此程序中，用户输入了进程的数量和时间片大小，然后输入每个进程的到达时间和执行时间。程序根据Round Robin算法执行，并计算出每个进程的等待时间和周转时间。最后，程序打印出每个进程的执行数据和平均等待时间和周转时间。