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I'm trying to do multilevel queue scheduling where

- priority==1 || priority==2 is using round robin in queue 1
- priority==3 || priority==4 is using first come first serve (fcfs) in queue 2
- priority > 4 is using fcfs in queue 3

the code that I've tried is incomplete but I try to run to see whether it works or not for the first 3 inputs, but there is an unknown error (I don't know what the error called) where the program run but it doesn't show any output and the program is not terminated.

process AT BT priority
p0 0 6 3
p1 1 4 3
p2 5 6 1

What I have tried:

public void sortMultilevel(int[] AT, int[] BT, int[] prio, int[] status, int TP)
	{
		int i=0, current=AT[i], j, test;
		while(TP!=0)
		{
			if(prio[i]==1 || prio[i]==2)
			{
				System.out.println("Queue 1:");
				System.out.print("p" + p[i] + " from " + current + " to ");
				// if(nonew())
				// {}
				// else {
				System.out.println(current+quantum);
				BT[i] = BT[i]-quantum;
				status[i]=1;
				current+=quantum;
				break;
				// }
			}
			else if(prio[i]==3 || prio[i]==4)
			{
				System.out.println("Queue 2:");
				System.out.print("p" + p[i] + " from " + AT[i] + " to ");
				// if(nonew())
				// {
					
				// }
				// else
				// {
					test=0;
					for(j=0; j<TP; j++)
					{
						if(AT[j]<current+BT[i])
						{
							if(prio[j]<prio[i])
							{
								System.out.println(AT[j]);
								BT[i] = BT[i]-(AT[j]-current);
								status[i]=1;
								current=AT[j];
								test=1;
								i=j;
								break;
							}
							else
							status[j]=1;
						}
						
					}
				// }
			}
		} // close while loop
	}
Posted
Updated 8-Sep-18 12:07pm
Comments
Richard MacCutchan 9-Sep-18 3:43am
   
Add some more print statements at the end of the while loop to see which variables are not changing. That's the best I can suggest as I cannot figure out what exactly that code is supposed to do.

1 solution

Quote:
The program is running but there's no output and the program is not terminated

What about watching you program performing to understand what is going on.

Your code do not behave the way you expect, or you don't understand why !

There is an almost universal solution: Run your code on debugger step by step, inspect variables.
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't know what your cpde is supposed to do, it don't find bugs, it just help you to by showing you what is going on. When the code don't do what is expected, you are close to a bug.
To see what your code is doing: Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.
Debugger - Wikipedia, the free encyclopedia[^]
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/jdb.html[^]
https://www.jetbrains.com/idea/help/debugging-your-first-java-application.html[^]
The debugger is here to only show you what your code is doing and your task is to compare with what it should do.
   
Comments
Member 13620781 8-Sep-18 23:42pm
   
may I know how to debug my java code in notepad++? I have searched it online and watched the youtube about it but I don't get it. Do I need to install dbgp plugin? sorry, but I'm really new in this field. Thank you in advance.
Patrice T 9-Sep-18 2:36am
   
I will not be of great help on this because I don't use NotePad++ or Java.
but there should be something useful in the 400000 answers of Google notepad++ java debugger

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