Ques3.c

#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
    int bt[20],at[10],n,i,j,temp,st[10],ft[10],wt[10],ta[10];    //bt - burst time ,wt - waiting time 
    int totwt=0,totta=0;                                         //at - arrival time ,ta - turn around time
    float awt,ata;                                               //st - starting time ,ft - finish time
    char pn[10][10],t[10];
    printf("Enter the number of process:");
    scanf("%d",&n);
    for(i=0; i<n; i++)
    {
    	re:
        printf("Enter process ID, arrival time& burst time:");
        scanf("%s%d%d",pn[i],&at[i],&bt[i]);
        if(at[i]==0)                                    //error if arrival time is zero
        {
        	printf("Arrival time cant be zero\nPlease Re-enter\n");
        	goto re;
		}
    }
    
    for(i=0; i<n; i++)
        for(j=0; j<n; j++)
        {
        	if(at[i]<=at[j])
            if(bt[i]<bt[j])
            {
                temp=at[i];
                at[i]=at[j];
                at[j]=temp;
                temp=bt[i];
                bt[i]=bt[j];
                bt[j]=temp;
                strcpy(t,pn[i]);
                strcpy(pn[i],pn[j]);
                strcpy(pn[j],t);
            }
        }
    for(i=0; i<n; i++)
    {
        if(i==0)
            st[i]=at[i];
        else
            st[i]=ft[i-1]+2;      //2 units of time after completion of each process
        wt[i]=st[i]-at[i];
        ft[i]=st[i]+bt[i];
        ta[i]=ft[i]-at[i];
        totwt+=wt[i];
        totta+=ta[i];
	}
    awt=(float)totwt/n;
    ata=(float)totta/n;
    printf("\nPname\tarrivaltime\texecutiontime\twaitingtime\ttatime");
    for(i=0; i<n; i++)
        printf("\n%s\t%5d\t\t%5d\t\t%5d\t\t%5d",pn[i],at[i],bt[i],wt[i],ta[i]);
    printf("\nAverage waiting time is:%f",awt);
    printf("\nAverage turnaroundtime is:%f",ata);
    getch();
}