Pre_Priority_Scheduling.java

package java_algo;

import java.util.Arrays;
import java.util.Scanner;

public class Pre_Priority_Scheduling {

	public static void main(String[] args) {

		System.out.println("*** Priority Scheduling ***");

		System.out.print("Enter Number of Process: ");
		Scanner sc = new Scanner(System.in);
		int numberOfProcess = sc.nextInt();
		String process[] = new String[numberOfProcess];

		int p = 1;
		for (int i = 0; i < numberOfProcess; i++) {
			process[i] = "P" + p;
			p++;
		}

		System.out.println(Arrays.toString(process));

		System.out.print("Enter Burst Time for " + numberOfProcess + " process: ");

		int burstTime[] = new int[numberOfProcess];
		for (int i = 0; i < numberOfProcess; i++) {
			burstTime[i] = sc.nextInt();
		}

		System.out.println(Arrays.toString(burstTime));

		System.out.print("Enter Priority for " + numberOfProcess + " process: ");

		int priority[] = new int[numberOfProcess];
		for (int i = 0; i < numberOfProcess; i++) {
			priority[i] = sc.nextInt();
		}

		System.out.println(Arrays.toString(priority));

// Sorting process & burst time by priority
		int temp;
		String temp2;
		for (int i = 0; i < numberOfProcess - 1; i++) {
			for (int j = 0; j < numberOfProcess - 1; j++) {
				if (priority[j] > priority[j + 1]) {
					temp = priority[j];
					priority[j] = priority[j + 1];
					priority[j + 1] = temp;

					temp = burstTime[j];
					burstTime[j] = burstTime[j + 1];
					burstTime[j + 1] = temp;

					temp2 = process[j];
					process[j] = process[j + 1];
					process[j + 1] = temp2;

				}
			}
		}

		int TAT[] = new int[numberOfProcess + 1];
		int waitingTime[] = new int[numberOfProcess + 1];

// Calculating Waiting Time & Turn Around Time
		for (int i = 0; i < numberOfProcess; i++) {
			TAT[i] = burstTime[i] + waitingTime[i];
			waitingTime[i + 1] = TAT[i];
		}

		int totalWT = 0;
		int totalTAT = 0;
		double avgWT;
		double avgTAT;

		System.out.println("Process     BT      WT        TAT");
		for (int i = 0; i < numberOfProcess; i++) {

			System.out.println(
					process[i] + "          " + burstTime[i] + "       " + waitingTime[i] + "         " + (TAT[i]));
			totalTAT += (waitingTime[i] + burstTime[i]);
			totalWT += waitingTime[i];

		}

		avgWT = totalWT / (double) numberOfProcess;
		avgTAT = totalTAT / (double) numberOfProcess;

		System.out.println("\n Average Wating Time: " + avgWT);
		System.out.println(" Average Turn Around Time: " + avgTAT);

	}

}