Homework help

[jamieexley]

what are the parameters needed in the constructor call below to create a Date variable whose intitial value is the 15th of March 2004????

[jamieexley]

thanks 4 the help

[PLA]

Given a list of integers and an integer variable declared like this:
List<Integer> list;
int max;

and assuming that some values have been added to the list,
What is the loop which finds the largest value in list and stores it in max?

  public static void main(String[] args)
  {
    List<Integer> list = new LinkedList<Integer>();
    int max = -999;
    list.add(1);
    list.add(12);
    list.add(2);
    list.add(11);
    for (int i : list)
    {
      if (i > max)
      {
        max = i;
      }
    }
    System.out.print("Max is : ");
    System.out.println(max);
  }
 

[jamieexley]

Thank u very much, appreciate that.

[jamieexley]

A bank account is stored as a Map which maps the names of the account holders to a value representing the current balance of their account:
Map<String,Inte ger> bank;

Given a String variable declared like this:
String rich = null;
How is the loop which will store the name of the person with the most money in their account in rich written?

[rivert1]

I was given this, can anyone shed some light on it????

How do write a method called countChars which takes an InputStream as a parameter, reads the stream and returns the number of characters it contains as an int. Any IOExceptions which might occur in the method should be passed back to the method's caller.

[PLA]

A bank account is stored as a Map which maps the names of the account holders to a value representing the current balance of their account:
Map<String,Inte ger> bank;

Given a String variable declared like this:
String rich = null;
How is the loop which will store the name of the person with the most money in their account in rich written?

Map<String, Integer> bank = new Hashtable<String, Integer>();
String rich = null;
Integer richBalance = new Integer(0);
 
    bank.put("aaa", new Integer(1020));
    bank.put("bbb", new Integer(2333));
    bank.put("ccc", new Integer(1356));
 
    for (String account : bank.keySet())
    {
      if (bank.get(account) > richBalance)
      {
        rich = account;
        richBalance = bank.get(rich);
      }
    }
    System.out.println("Max is : " + rich + " (" + richBalance + ")");
 

It's my last for that day!

[jamieexley]

Just 1 more! Please
(3rd & Final)

Using the same bank account as in the previous question, and a list of strings:
Map<String,Inte ger> bank;
List<String> names;

I need to write a loop which fills the list names with the names of all account holders whose accounts are overdrawn, i.e. the balance of their account is less than zero???

[PLA]

Just 1 more! Please
(3rd & Final)

Using the same bank account as in the previous question, and a list of strings:
Map<String,Inte ger> bank;
List<String> names;

I need to write a loop which fills the list names with the names of all account holders whose accounts are overdrawn, i.e. the balance of their account is less than zero???

    Map<String, Integer> bank = new Hashtable<String, Integer>();
    String rich = null;
    Integer richBalance = new Integer(0);
    List<String> names = new LinkedList<String>();
 
    bank.put("aaa", new Integer(1020));
    bank.put("bbb", new Integer(2333));
    bank.put("ccc", new Integer(-1356));
    bank.put("ddd", new Integer(1356));
    bank.put("eee", new Integer(-56));
 
    for (String account : bank.keySet())
    {
      if (bank.get(account) > richBalance)
      {
        rich = account;
        richBalance = bank.get(rich);
      }
      if (bank.get(account) < 0)
      {
        names.add(account);
      }
    }
    System.out.println("Max is : " + rich + " (" + richBalance + ")");
    System.out.println("Names are : " + names);
 

It is easy as you can see !!!

[PLA]

In fact it is the first time I use Generics in Java (I remembered ugly code and response time in C++ with templates) and it's quite good. Thanks for the lesson

[D_C]

I don't know how list is defined, but this may give you an idea of how to do it. I am assuming there are list.length() elements in the list, and list.entry(i) returns the ith element. Similarly for map. I will give you an idea for #2, and some suggestions for the others.

Number 2

max = map.entry(0).getInt(); // since list is not empty.
for(int i = 0; i < map.length(); i++)
{
   if(max < map.entry(i).getInt())
   {
      max = map.entry(i).getInt());
      rich = map.entry(i).getStr());
   }
}

#1. Just like #2, only you don't worry about the string rich. Also it's a list instead of a map.
#3. Change the if statement. It's condition is given to you. The code to execute should simply put the person's name into a list.

The others seem just as trivial. Give it a go yourself, and if you have any trouble, post your code, what's wrong with it, and what you can't figure out. Then we'll look at it and see.