进程调度算法实验报告c语言

以下是进程调度算法实验报告的C语言代码：

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

#define MAX_PROCESS 10

typedef struct {
    int pid;
    int burst_time;
    int arrival_time;
    int waiting_time;
    int turnaround_time;
} process;

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

int main() {
    int n, i, quantum;
    process p[MAX_PROCESS];

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

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

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

    printf("Enter time quantum: ");
    scanf("%d", &quantum);
    rr(p, n, quantum);

    return 0;
}

void fcfs(process *p, int n) {
    int i, total_waiting_time = 0, total_turnaround_time = 0;

    p[0].waiting_time = 0;

    for (i = 1; i < n; i++) {
        p[i].waiting_time = p[i - 1].waiting_time + p[i - 1].burst_time;
    }

    for (i = 0; i < n; i++) {
        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;
    }

    printf("\nFCFS Scheduling:\n");
    printf("Process\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, p[i].waiting_time, p[i].turnaround_time);
    }

    printf("Average waiting time = %.2f\n", (float) total_waiting_time / n);
    printf("Average turnaround time = %.2f\n", (float) total_turnaround_time / n);
}

void sjf(process *p, int n) {
    int i, j, min, total_waiting_time = 0, total_turnaround_time = 0;
    process temp;

    for (i = 0; i < n - 1; i++) {
        min = i;

        for (j = i + 1; j < n; j++) {
            if (p[j].burst_time < p[min].burst_time) {
                min = j;
            }
        }

        if (min != i) {
            temp = p[i];
            p[i] = p[min];
            p[min] = temp;
        }
    }

    p[0].waiting_time = 0;

    for (i = 1; i < n; i++) {
        p[i].waiting_time = p[i - 1].waiting_time + p[i - 1].burst_time;
    }

    for (i = 0; i < n; i++) {
        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;
    }

    printf("\nSJF Scheduling:\n");
    printf("Process\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, p[i].waiting_time, p[i].turnaround_time);
    }

    printf("Average waiting time = %.2f\n", (float) total_waiting_time / n);
    printf("Average turnaround time = %.2f\n", (float) total_turnaround_time / n);
}

void rr(process *p, int n, int quantum) {
    int i, j, time = 0, remaining = n, total_waiting_time = 0, total_turnaround_time = 0;
    process temp;

    for (i = 0; i < n - 1; i++) {
        for (j = i + 1; j < n; j++) {
            if (p[i].arrival_time > p[j].arrival_time) {
                temp = p[i];
                p[i] = p[j];
                p[j] = temp;
            }
        }
    }

    for (i = 0; i < n; i++) {
        p[i].waiting_time = 0;
    }

    while (remaining > 0) {
        for (i = 0; i < n; i++) {
            if (p[i].burst_time > 0) {
                if (p[i].burst_time <= quantum) {
                    time += p[i].burst_time;
                    p[i].burst_time = 0;
                    p[i].turnaround_time = time - p[i].arrival_time;
                    p[i].waiting_time = p[i].turnaround_time - p[i].burst_time;

                    total_waiting_time += p[i].waiting_time;
                    total_turnaround_time += p[i].turnaround_time;

                    remaining--;
                } else {
                    time += quantum;
                    p[i].burst_time -= quantum;
                }
            }
        }
    }

    printf("\nRound Robin Scheduling:\n");
    printf("Process\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, p[i].waiting_time, p[i].turnaround_time);
    }

    printf("Average waiting time = %.2f\n", (float) total_waiting_time / n);
    printf("Average turnaround time = %.2f\n", (float) total_turnaround_time / n);
}

此代码使用了三种不同的进程调度算法：先来先服务（FCFS）、短作业优先（SJF）和轮转调度（RR）。用户需要输入每个进程的到达时间和执行时间，然后程序将计算每个进程的等待时间和周转时间，并输出平均等待时间和平均周转时间。

在FCFS算法中，进程按照它们到达的顺序执行。在SJF算法中，进程按照它们的执行时间排序，然后按照顺序执行。在RR算法中，进程按照它们到达的顺序排序，然后每个进程都被分配一个时间量（量子），在这个时间量内执行，如果进程还没有完成，那么它重新排队，等待下一次执行。

希望这个代码对你有所帮助！