操作系统先到先服务算法c语言代码

下面是一个简单的 C 语言代码实现先到先服务算法（FCFS）：

#include <stdio.h>

int main() {
    int n, bt[20], wt[20], tat[20], avwt = 0, avtat = 0, i, j;
    printf("Enter total number of processes: ");
    scanf("%d", &n);
    
    printf("Enter process burst time:\n");
    for (i = 0; i < n; i++) {
        printf("P[%d]: ", i + 1);
        scanf("%d", &bt[i]);
    }
    
    wt[0] = 0; // Waiting time for first process is 0
    
    // Calculate waiting time for each process
    for (i = 1; i < n; i++) {
        wt[i] = 0;
        for (j = 0; j < i; j++) {
            wt[i] += bt[j];
        }
    }
    
    printf("\nProcess\t\tBurst time\tWaiting time\tTurnaround time");
    
    // Calculate turnaround time and average waiting time and turnaround time
    for (i = 0; i < n; i++) {
        tat[i] = bt[i] + wt[i];
        avwt += wt[i];
        avtat += tat[i];
        printf("\nP[%d]\t\t%d\t\t%d\t\t%d", i + 1, bt[i], wt[i], tat[i]);
    }
    
    avwt /= i;
    avtat /= i;
    printf("\n\nAverage waiting time: %d", avwt);
    printf("\nAverage turnaround time: %d", avtat);
    
    return 0;
}

该代码首先要求用户输入进程数量和每个进程的 CPU 周转时间（burst time），然后计算每个进程的等待时间（waiting time）。最后，它输出每个进程的周转时间（turnaround time）、等待时间、和平均等待时间和周转时间。