OOP logic??

[Noogie]

Hello all... greenest newbie on earth here - looking for help.

I am taking a class called OOP Logic and Design. It's a prerequisite to all OOP Language classes unfortunately. I thought it would be so enlightening - and maybe it still will be - but at the moment, i'm thoroughly confused. :p

Writing blind pseudo-code that you can't test or execute makes it difficult to understand what you are doing. Also, the book is so .... thorough, i guess...that picking out the high-points - the things that'll help when it's time for homework - is near impossible. That being said, and being only a few chapters in, I have a simple assignment this week. Yet some of the logic is lost on me - since we're writing this pseudo-code in a vacuum.

Here is one of the exercises:

"Rick Hammer is a carpenter who wants an application to compute the price of any desk a customer orders, based on the following: desk length and width in inches, type of wood, and number of drawers. The price is computed as follows:

- The charge for all desks is a minimum of $200
- If the surface (length*width) is over 750 sq in, add $50
- If the wood is 'mahogany' add $150; oak add $125. No charge is added for pine.
- For every drawer in the desk, there is an additional $30 charge.

Design:
A. an 'Order' class including order number, customer name etc, and all the fields mentioned above. Include get and set methods for each field.

B. An application that accepts an 'Order' and displays all the relevant info and the price."

I should add that this follows a chapter on flowcharting. I believe they are looking for us to use what we learned - ie: utilize a case structure for one item like woodType, etc.

So far, I've declared my variables, wrote the set/get statements including (hopefully) decent calculations for the price variables.

The application part is hairier for me, and I'm not sure what I'm doing. Been digging through my book but i'm still kind of lost. (their examples are always just a couple of lines of pseudo-code for the particular topic, thus rendering it basically useless when you're trying to structure everything together )

*sigh*

If anyone has an urge to help me get this down on paper and understand what I did, i'd be most grateful. I'm not willing to bypass understanding the basic class, method and structure information they're trying to impart because the book sucks. :p

Forever grateful,
Jacquie

[DJMaze]

how are you writing your application? C++, C#, .NET, .NET2, Delphi, Java, PHP 5, etc. ?

[Noogie]

Originally Posted by DJMaze

how are you writing your application? C++, C#, .NET, .NET2, Delphi, Java, PHP 5, etc. ?

no language. strictly pseudo-code.

[sde]

here is some quick code i wrote that meets the criteria i think.. you could probably use it as a base line for your psuedo code

hey djm, isn't there a slick get/set model for PHP 5 classes?

PHP Code:

<?
class Order
{
  public $orderNumber;
  public $customerName;
  public $length;
  public $width;
  public $woodType;
  public $drawerCount;
  public $totalCost;

  public function setOrderNumber($orderNumber)
  {
    $this->orderNumber = $orderNumber;
  }

  public function getOrderNumber()
  {
    return $this->orderNumber;
  }

  public function setCustomerName($customerName)
  {
    $this->customerName = $customerName;
  }

  public function getCustomerName()
  {
    return $this->customerName;
  }
  
  public function setLength($length)
  {
    $this->length = $length;
  }

  public function getLength()
  {
    return $this->length;
  }
  
  public function setWidth($width)
  {
    $this->width = $width;
  }

  public function getWidth()
  {
    return $this->width;
  }
  
  public function setWoodType($woodType)
  {
    $this->woodType = $woodType;
  }

  public function getWoodType()
  {
    return $this->woodType;
  }
  
  public function setDrawerCount($drawerCount)
  {
    $this->drawerCount = $drawerCount;
  }

  public function getDrawerCount()
  {
    return $this->drawerCount;
  }
  
  public function setTotalCost($totalCost)
  {
    $this->totalCost = $totalCost;
  }
  
  public function getTotalCost()
  {
    return $this->totalCost;
  }
  
  public function calculateTotalCost()
  {
    $cost = 200;
      
    // check surface for cost
    if (($this->getWidth() * $this->getHeight()) > 750) {
      // add fifty bucks
      $cost += 50;
    }
      
    // check wood for cost
    switch ($this->getWoodType()) {
          
      case "mahogany":
        $cost += 150;
        break;
              
      case "oak":
        $cost += 125;
    }
    
    // check drawer count for cost
    $cost += $this->getDawerCount()*30;
    
    // set total cost
    setTotalCost($cost);
  }
}

// example use
$order = new Order();

$order->setOrderNumber(12345);
$order->setCustomerName("John Smith");
$order->setLength(24);
$order->setWidth(48)
$order->setWoodType("oak");
$order->setDrawerCount(4);

$order->calculateTotalCost();
?>

[teknomage1]

I thought there was a rule somewhere that all object oriented psuedo code has to be either in smalltalk or object pascal.

[redhead]

I thought there was a rule somewhere that all object oriented psuedo code has to be either in smalltalk or object pascal.

Hmm.. I always thought Emerald was a decent way to write pseudo OO code in.

[Noogie]

SDE, Thank you for doing that...it was very helpful! I owe you!

Here is what I have so far - remember, this is just generic pseudocode that I need to turn in with no shortcuts/abbreviations etc. One thing I'm confused about. In the application class, when I get the different variables, do I need to initialize those? I did for OrderNumber as I can enter a starting value but the others i am not sure about.....

Please let me know if you see any problems with structure, how i've calculated the totalCost or with the use of public/private (should the calculations be private?) or void/static. These are the details I don't have confidence in yet... You guys are more helpful than my book or instructor.

Class Order

	private numeric orderNumber
	private string custLName
	private string custFName
	private string custStrAddr
	private string custCity
	Private string custState
	private string custZip
	private string custTelNo
	private numeric length
	private numeric width
	private string woodType
	private numeric drawerCount
	private numeric totalCost
		



	public numeric getOrderNumber()
	return orderNumber

	public void setOrderNumber(numeric num)
	       orderNumber = num
	return
	

	public string getCustLName()
	return custLName

	public void setCustLName(string lastName)
	       custLName = lastName
	return


	public string getCustFName()
	return custFName

	public void setCustFName(string firstName)
	       custFName = firstName
	return


	public string getCustStrAddr()
	return CustStrAddr

	public void setCustStrAddr(string address)
	       CustStrAddr = address
	return


	public string getCustCity()
	return CustCity

	public void setCustCity(string city)
	       custCity = city
	return


	public string getCustState()
	return CustState


	public void setCustState(string state)
	       custState = state
	return


	public string getCustZip()
	return custZip

	public void setCustZip(string zipCode)
		custZip = zipCode
	return


	public string getCustTelNo()
	return CustTelNo

	public void setCustTelNo(string telNo)
		custTelNo = telNo
	return


	public numeric getDeskLength()
	return deskLength

	public void setDeskLength(numeric num)
		deskLength = length
	return 

	public numeric getDeskWidth()
	return deskWidth  

	public void setDeskWidth(numeric num)
	       deskWidth = width
	return
	
	public string getWoodType()
	return woodType

	public void setWoodType(string wood)
		woodType = wood
	return

	public numeric getDrawerCount()
	return drawerCount

	public void setDrawerCount(numeric drawers)
		DrawerCount = drawers
	return

	public numeric getTotalCost()
	return totalCost

	
	public void calculateTotalCost()
		numeric totalCost = 200
		
		case based on woodType
			case "Pine"
			     totalCost = 200
			case "Oak"
			     totalCost = 325 
			case "mahogany"
			     totalCost = 350
			default
			     totalCost = 200
			     print "Error - Enter valid wood type"
		endcase

		if deskLength * deskWidth > 750 then	
			     totalCost = totalCost + 50
		        default
		             totalCost = totalCost
		             print "Error - Enter dimensions of desk"		 		  
		endif

		if drawerCount > 0 then		
			    totalCost = totalCost + (drawerCount * 30)
		        default
			    totalCost = totalCost
		            print "Error - Enter number of desk drawers" 				 
		endif
	return
endClass



class NewDesk
	public static void main()
		Order desk

		desk.setOrderNumber(123)
		desk.setCustFName()
	        desk.setCustLName()
	 	desk.setCustStrAddr()
	 	desk.setCustCity()
	 	desk.setCustState()
	 	desk.setCustZip()
	 	desk.setCustTelNo()
	 	desk.setTotalCost()
		

		print "Order Number:", desk.getOrderNumber(123)
		print "Price:", desk.getPrice()
		print "First Name:", desk.getCustFName()
	        print "Last Name:", desk.getCustLName()
	 	print "Address:", desk.getCustStrAddr()
	 	print "City:", desk.getCustCity()
	 	print "State:", desk.getCustState()
	 	print "Zip Code:", desk.getCustZip()
	 	print "Phone Number:", desk.getCustTelNo()
	 	print "Custom Details:"
		print "Desk Dimensions:", desk.getLength(), "by" desk.getWidth()
		Print "Wood Type:", desk.getWoodType()
		print "Number of Drawers:", desk.getDrawerCount()
		print "Total Cost", desk.getTotalCost()
		print "Rick thanks you for your business!"
	return
endClass

[sde]

yeah, you should probably initialize the variables in a constructor function. i'm not sure what it would look like in your psuedo code but a lot of languages use a function that has the same name as the class.

i.e: public void Order(){}

There you can initialize your variables to the type of var you defined.

customerName = "";
orderNumber = 0;

looks like you are using void appropriately.

[DJMaze]

Originally Posted by sde

hey djm, isn't there a slick get/set model for PHP 5 classes?

Correct

PHP Code:

<?php

class aphp5class
{
    # overloaders don't use the private, protected and public member definition
    function __get($key)
    {
        if (isset($this->$key))
        {
            return $this->$key;
        }
        else
        {
            throw new Exception($key.' does not exist');
        }
    }

    function __set($key, $value)
    {
        if (isset($this->$key))
        {
            $this->$key = $value;
            mysql_query('UPDATE table SET '.$key.'=\''.$value.'\'');
        }
        else
        {
            throw new Exception($key.' does not exist');
        }
    }

}

[Noogie]

Originally Posted by sde

yeah, you should probably initialize the variables in a constructor function. i'm not sure what it would look like in your psuedo code but a lot of languages use a function that has the same name as the class.

i.e: public void Order(){}

There you can initialize your variables to the type of var you defined.

customerName = "";
orderNumber = 0;

looks like you are using void appropriately.

thanks sde, i did work on initializing them - i think i did it right.

On top of this fun, my instructor is a British dude who writes things like "you can't do that!!!" and "where's your end statement???"

I can't bear his indignation again! :p

[teknomage1]

From a semantic standpoint, it seems hard to argue about syntax errors in psuedo code given the wide range of grammars for real programming languages. I mean what if my psuedo grammar makes all end tags implicit via indentation (like python)?