SJF.c

// C program to implement Shortest Job First

#include<stdio.h>
#include<conio.h>
void main()
{
    int bt[20],p[20],wt[20],tat[20],i,j,n,total=0,pos,temp;
    float avg_wt,avg_tat;
    printf("\n\nEnter number of process: ");
    scanf("%d",&n);

    for(i=0;i<n;i++)
    {
	printf("Enter burst time for process %d: ",i+1);
	scanf("%d",&bt[i]);
	p[i]=i+1;
    }

    for(i=0;i<n;i++)
    {
	pos=i;
	for(j=i+1;j<n;j++)
	{
	    if(bt[j]<bt[pos])
		pos=j;
	}

	temp=bt[i];
	bt[i]=bt[pos];
	bt[pos]=temp;

	temp=p[i];
	p[i]=p[pos];
	p[pos]=temp;
    }

    wt[0]=0;
    for(i=1;i<n;i++)
    {
	wt[i]=0;
	for(j=0;j<i;j++)
	    wt[i]+=bt[j];

	total+=wt[i];
    }

    avg_wt=(float)total/n;
    total=0;

    printf("\nProcess\t    Burst Time    \tWaiting Time\tTurnaround Time");
    for(i=0;i<n;i++)
    {
	tat[i]=bt[i]+wt[i];
	total+=tat[i];
	printf("\nprocess %d\t  %d\t\t    %d\t\t\t%d",p[i],bt[i],wt[i],tat[i]);
    }

    avg_tat=(float)total/n;
    printf("\n\nAverage Waiting Time=%f",avg_wt);
    printf("\nAverage Turnaround Time=%f\n",avg_tat);
    getch();
}