SJF
#include <stdio.h>
#include <stdlib.h>
int main()
{
int i, n, p[10], min, k = 1, btime = 0;
int bt[10], temp, j, at[10], wt[10], tt[10], ta = 0, sum = 0;
float wavg = 0, tavg = 0, tsum = 0, wsum = 0;
printf("Short Job First Scheduling Algorithm\n");
printf("Enter no. of process : ");
scanf("%d",&n);
for( i = 0; i < n; ++i )
{
p[i]=i+1;
printf("\n\nEnter arrival time of %d process: ",i+1);
scanf("%d",&at[i]);
printf("Enter the burst time of %d process: ", i+1 );
scanf("%d",&bt[i]);
}
for( i = 0; i < n; ++i )
{
for( j = 0; j < n; ++j )
{
if( at[i] < at[j] )
{
temp = p[j];
p[j] = p[i];
p[i] = temp;
temp = at[j];
at[j] = temp;
temp = bt[j];
bt[j] = bt[i];
bt[i] = temp;
}
}
}
for( j = 0; j < n; ++j )
{
btime = btime+bt[j];
min = bt[k];
for( i = k; i < n; ++i )
{
if( btime >= at[i] && bt[i] < min )
{
temp = p[k];
p[k] = p[i];
p[i] = temp;
temp = at[k];
at[k] = at[i];
at[i] = temp;
temp = bt[k];
bt[k] = bt[i];
bt[i] = temp;
}
}
++k;
}
wt[0] = 0;
for( i = 1; i < n; ++i )
{
sum = sum + bt[i-1];
wt[i] = sum-at[i];
wsum += wt[i];
}
wavg = wsum/n;
for( i = 0; i < n; ++i )
{
ta = ta + bt[i];
tt[i] = ta - at[i];
tsum += tt[i];
}
tavg = tsum/n;
printf("\nProcess\tBT\tAT\tWT\tTAT\n");
for(i=0;i<n;++i)
printf("\nP%d\t%d\t%d\t%d\t%d\n",p[i],bt[i],at[i],wt[i],tt[i]);
printf("\nAverage waiting time : %.2f",wavg);
printf("\nAverage turn around time : %.2f",tavg);
return 0;
}
/*
INPUT/OUTPUT :
-------------
Short Job First Scheduling Algorithm
Enter no. of process : 4
Enter arrival time of 1 process: 0
Enter the burst time of 1 process: 3
Enter arrival time of 2 process: 0
Enter the burst time of 2 process: 6
Enter arrival time of 3 process: 0
Enter the burst time of 3 process: 7
Enter arrival time of 4 process: 0
Enter the burst time of 4 process: 8
Process BT AT WT TAT
P1 3 0 0 3
P2 6 0 3 9
P3 7 0 9 16
P4 8 0 16 24
Average waiting time : 7.00
Average turn around time : 13.00
*/
Sam the WatchDogs