C Program to Simulate Priority Scheduling CPU scheduling Algorithm

The following C program implements Simulation of  priority scheduling (CPU Scheduling algorithm). Each process or job is given a priority. The priority is represented using a positive integer. The priority increases as the value of the integer decreases.

Program:

#include<stdio.h>
struct process{



int burst,wait,no,priority;
}p[20]={0,0};
int main(){
int n,i,j,totalwait=0,totalturn=0;
printf("\nEnter The No Of Process :");
scanf("%d",&n);
for(i=0;i<n;i++){
printf("Enter The Burst Time (in ms) For Process #%2d :",i+1);
scanf("%d",&p[i].burst);
printf("Enter The Priority For Process #%2d :",i+1);
scanf("%d",&p[i].priority);
p[i].no=i+1;
}
for(i=0;i<n;i++)
for(j=0;j<n-i-1;j++)
if(p[j].priority>p[j+1].priority)
{
p[j].burst^=p[j+1].burst^=p[j].burst^=p[j+1].burst;
p[j].no^=p[j+1].no^=p[j].no^=p[j+1].no;
//Simple way to swap 2 var’s
p[j].priority^=p[j+1].priority^=p[j].priority^=p[j+1].priority;
//printf("j");
}
printf("\nProcess \t Starting\tEnding\tWaiting\tTurnAround ");
printf("\n\t Time\tTime\tTime\tTime ");
for(i=0;i<n;i++)
{
printf("\nProcess # %-11d%-10d%-10d%-10d%10d",p[i].no,p[i].wait,p[i].wait+p[i].burst,p[i].wait,p[i].wait+p[i].burst);
p[i+1].wait=p[i].wait+p[i].burst;
totalwait=totalwait+p[i].wait;
totalturn=totalturn+p[i].wait+p[i].burst;
}
printf("\n\nAverage\n---------");
printf("\nWaiting Time : %f ms",totalwait/(float)n);
printf("\nTurnAround Time : %f ms\n\n",totalturn/(float)n);
return 0;
}

Output:
Enter The No Of Process :3
Enter The Burst Time (in ms) For Process #1 :30
Enter The Priority For Process # 1 :2
Enter The Burst Time (in ms) For Process #2 :20
Enter The Priority For Process # 2 :1
Enter The Burst Time (in ms) For Process #3 :40
Enter The Priority For Process # 3 :3

Process          Starting  Ending  Waiting  TurnAround
                          Time        Time      Time          Time
Process # 2        0             20           0                20
Process # 1       20            50          20              50
Process # 3       50            90          50              90

Average
---------
Waiting Time : 23.333333 ms
TurnAround Time : 53.333333 ms