Untitled

import java.util.*;

public class SRTF {
    static void getSRTF(){
        Scanner in = new Scanner(System.in);
        int n;
        System.out.print("Enter the # of Processes: ");
        n = in.nextInt();   // get num of processes of user
        int myProcess[][] = new int[n + 1][4]; // initialize array to store values
        int Orig_Burst_t[] = new int[n + 1]; // this array is used to store the original value of the burst Time of the processes
        // myProcess[][0] = Arrival time
        // myProcess[][1] = Burst time
        // myProcess[][2] = Wait time
        // myProcess[][3] = Total time
        for(int i = 1; i <= n; i++)
        {
            System.out.println("\n\t[P" + i +"]");
            System.out.print("Arrival Time: ");
            myProcess[i][0] = in.nextInt(); // get Arrival Time
            System.out.print("Burst Time: ");
            myProcess[i][1] = in.nextInt(); // get Burst Time
            Orig_Burst_t[i] = myProcess[i][1]; // store the original burst time for output later

        }
        System.out.println();

        //This part is the calculation of total time and the initialization of gantt chart array
        int total_t = 0;    // initialize total time to 0
        for(int i = 1; i <= n; i++) {
            total_t += myProcess[i][1]; // sums up all the burst times of all processes
        }

        int gantt_chart[] = new int[total_t];    // make gantt array who's size is the total time (total_t is the sum of all burst times)

        for(int i = 0; i < total_t; i++)
        {
            // this part will pick the shortest process that has arrived
            int select_process = 0;
            int minimum = 999;

            for(int j = 1; j <= n; j++)
            {
                if(myProcess[j][0] <= i)    //this condition checks if Process (arrival time) has been called
                {
                    if(myProcess[j][1] < minimum && myProcess[j][1] != 0) // if burst time < minimum and burst time != 0 then execute
                    {
                        minimum = myProcess[j][1]; // update the minumum to the selected burst time
                        select_process = j;        // update the select_process to the number of j selected
                    }
                }
            }


            gantt_chart[i] = select_process; // add the selected_press to the respected index it belongs in the gantt chart.

            myProcess[select_process][1]--; // decrement the burst time of the selected process by 1 since it had used 1 unit of time


            //Waiting Time and Total Time Calculations
            for(int j = 1; j <= n; j++)
            {
                if(myProcess[j][0] <= i)    //this condition checks if Process has been called
                {
                    if(myProcess[j][1] != 0) // if burst time != 0; execute
                    {
                        myProcess[j][3]++; //   increment TotalTime by 1 if the process has been called and execution is not yet complete

                        if(j != select_process) // if j != the selected process increment the Waiting Time by 1
                            myProcess[j][2]++;
                    }
                    else if(j == select_process)// if process has been assigned CPU and has completed its execution increment the total time by 1
                        myProcess[j][3]++;
                }
            }

            //Printing the gantt chart
            if(i != 0){
                if(select_process != gantt_chart[i - 1]){ // We must print the current time and the name of the new Process if the CPU has been given to a different Process.
                    System.out.print(" | " + i + " | P" + select_process);
                }
            }
            else {  //If the current time is 0, print the first selected process
                System.out.print(i + " | P" + select_process);
            }
            if(i == total_t - 1) // by this point all processes have been called and we need to print the last value of the time of execution
                System.out.print(" | " + (i + 1));

        }
        System.out.println();
        System.out.println();

        //Printing the Waiting time and Total time for each Process
        System.out.println("Process\t\t\t Arrival Time \t\t\t Burst Time \t\t\t Waiting Time \t\t\t Turnaround Time ");
        for(int i = 1; i <= n; i++)
        {
            System.out.printf("%4d\t%16d\t%19d\t%22dms\t%19dms",i,myProcess[i][0],Orig_Burst_t[i],myProcess[i][2],myProcess[i][3]);
            System.out.println();
        }

        System.out.println();

        //Printing the average Waiting time & Total time

        // initalize variables to store the total waiting time & total time
        float print_waitingtime = 0;
        float print_totaltime = 0;
        for(int i = 1; i <= n; i++){    // add all occurrences of waiting time and total time inside the variable
            print_waitingtime += myProcess[i][2];
            print_totaltime += myProcess[i][3];
        }
        // divide by number of processes that was initialized by the user (n)
        print_waitingtime /= n; // print_waitingtime = print_waitingtime / n
        print_totaltime /= n;   // print_totaltime = print_totaltime / n

        System.out.println("The Average Waiting Time is: " + print_waitingtime + "ms");
        System.out.println("The Average Total Time is: " + print_totaltime + "ms");
    }
}