Java Sorting Question

DaZulu

Have to do this for a college Java project http://homepage.eircom.net/~iandowney/m2pra.htm. Basically I have everything done except the last bit of PartC: "The report should be capable of being provided in order of prison number or in order of surname." I have no clue how to go about this. Do you use the java sort method? and if so how? Thanks in advance!

public class prisonManager3
{
public static void main(String[]args)
{
System.out.println(" ");
System.out.println("WELCOME TO PRISON MANAGER");
System.out.println(" ");

//create array of prisoners
prisoner [] inmate = new prisoner[3];


System.out.println("Enter details for each inmate.");

for(int i=0;i<inmate.length;i++)
{
inmate = new prisoner();

//enter inmate details
inmate.setName();
inmate.setAge();
inmate.setSentence();
inmate.setNumber();
inmate.setCellnum(i);

System.out.println("Inmate Recorded");
}


int maxAge = 0, minAge = 999, maxSentence = 0, sentenceCount = 0, youngestCount = 0;

//check for other details

for(int i=0;i<inmate.length;i++)
{
if(inmate.age > maxAge)
{
maxAge = inmate.age;
}

if(inmate.age < minAge)
{
minAge = inmate.age;
youngestCount = inmate.pnum;
}


if(inmate.sentence > maxSentence)
{
maxSentence = inmate.sentence;
sentenceCount = inmate.cellNum;
}
}


for(int i=0;i<inmate.length;i++)
{
System.out.println(" ");
System.out.println("#" + inmate.getNumber());
System.out.println("Name: " + inmate.getSurname() + ", " + inmate.getForename());
System.out.println("Age: " + inmate.getAge());
System.out.println("Sentence: " + inmate.getSentence() + " years");
System.out.println(" ");
}

//print other details
System.out.println("The eldest inmate is " + maxAge + " years old.");
System.out.println("#" + youngestCount + " is the youngest inmate.");
System.out.println("Cell #" + sentenceCount + " is serving the longest sentence.");

int yearsCount = 0;

System.out.println(" ");
System.out.println(" ");

for(int j=0;j<inmate.length;j++)
{
sentenceCount = inmate[j].sentence / 2;

for(int i=0;i<100;i++)
{
inmate[j].age += 1;
inmate[j].sentence -= 1;

if(inmate[j].age == 70 || inmate[j].sentence == sentenceCount)
{
i = 100;
System.out.println("#" + inmate[j].pnum + " will be released after " + yearsCount + " years.");
}
else
{
yearsCount += 1;
}
}
}

System.out.println(" ");
System.out.println(" ");
System.out.println("!PROGRAM END!");
System.exit(0);
}
}

Separate class:

class prisoner
{
String forename, surname;
int age, sentence, pnum=47, cellNum;



public void setName()
{
forename=getit.forename();
surname=getit.surname();
}

public String getForename()
{
return forename;
}

public String getSurname()
{
return surname;
}




public void setAge()
{
age=getit.age();
}

public int getAge()
{
return age;
}




public void setSentence()
{
sentence=getit.sentence();
}

public int getSentence()
{
return sentence;
}




public void setNumber()
{
double num;
num=Math.random();
num=num * 100;
num = Math.round(num);
pnum = (int)num;
}

public int getNumber()
{
return pnum;
}




public void setCellnum(int i)
{
cellNum=i + 1;
}

}

seamus

Do a search for sorting algorithms. Since there are only 100 prisoners, even a standard linear sort shouldn't be too slow, but a better algorithm will look better and is good experience.

If you're interested in Object-Oriented Programming (and making a good impressions on lecturers), try to write it in the Object style. Instead of one class doing everything, have two, maybe three classes. Most obviously, a Prisoner class which would take a few variables (forename, surname, age, sentence, prisoner number) and then on creation calculate the earliest possible release time.

Then you could also have a Prison class, which operates on an array of Prisoner Objects, and providing such methods as addPrisoner(), releasePrisoner(), and also to provide the desired reports for returning the list of Prisoners, sorted what ever way you want.

lynchie

Also look at the Javadocs for Collections.sort() methods

Giblet

Arrays.sort() in java.util

Make inmate.getSurname an object, and sort.

Arrays.sort(SurnameObject)

tempest

lynchie wrote:

Also look at the Javadocs for Collections.sort() methods

And Arrays.sort() methods and the java.util.Comparator interface.....

DaZulu

Thanks for the help. My fourth post since 2001 - a success, lol