FCFS1.c

//To impleament FCFS (first come first service) CPU scheduling

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

struct data
{
    int id, at, bt, wt, tat, ct;
};
struct data *process = NULL;

void create_data(int n)
{
    //this function create the processes

    int i;
    process = (struct data *)calloc(n, sizeof(struct data));

    for (i = 0; i < n; i++)
    {
        printf("\nEnter the data --->\n");
        printf("Enter process id : ");
        scanf("%d", &process[i].id);
        printf("Enter Arrival Time : ");
        scanf("%d", &process[i].at);
        printf("Enter Burst Time : ");
        scanf("%d", &process[i].bt);
    }
}
void sort_at(int n)
{
    //this function sort the processes according to their arrival time
    int i, j, min;
    struct data tmp;

    for (i = 0; i < n - 1; i++)
    {
        min = i;
        for (j = i + 1; j < n; j++)
        {
            if (process[i].at > process[j].at)
                min = j;
        }
        if (i != j)
        {
            tmp = process[i];
            process[i] = process[min];
            process[min] = tmp;
        }
    }
}
void assign_data(int n)
{
    //this function calculate and assign the waiting time,turnaround time etc.
    int i;
    sort_at(n);
    for (i = 0; i < n; i++)
    {
        if (i == 0)
        {
            process[i].wt = 0;
            process[i].ct = process[i].at + process[i].bt;
            process[i].tat = process[i].ct - process[i].at;
        }
        else
        {
            process[i].ct = process[i - 1].ct + process[i].bt;
            process[i].tat = process[i].ct - process[i].at;
            process[i].wt = process[i].tat - process[i].bt;
        }
    }
}
void display(int n)
{
    //this function display the data of processes and avg. waiting time , CPU utilization etc.

    int i, avg_wt = 0, avg_tat = 0, ct = 0, total_bt = 0;
    float cpu_utl = 0;
    printf("\nP Id\t Arrival Time\tBurst Time\tWaiting Time\tTurnaround Time\tCompletion Time\n");

    for (i = 0; i < n; i++)
    {
        printf("\n%d\t\t", process[i].id);
        printf("%d\t\t", process[i].at);
        printf("%d\t\t", process[i].bt);
        printf("%d\t\t", process[i].wt);
        printf("%d\t\t", process[i].tat);
        printf("%d\t\t", process[i].ct);

        avg_wt += process[i].wt;
        avg_tat += process[i].tat;
        total_bt += process[i].bt;
        ct = process[i].ct;
    }
    cpu_utl = ((float)total_bt / (float)ct) * 100;

    printf("\n\n\nAverage Turnaround Time : %.2f", (float)avg_tat / n);
    printf("\n\nAverage Waiting Time : %.2f", (float)avg_wt / n);
    printf("\n\nThroughput : %.2f", (float)n / (float)ct);
    printf("\n\nCPU Utilization : %.2f", cpu_utl);
    printf("\n\nCPU Idealness : %.2f", (100 - cpu_utl));
}
int main(void)
{
    int n;

    printf("Enter the no of process : ");
    scanf("%d", &n);
    create_data(n);
    assign_data(n);
    display(n);
    return 0;
}