Create Vector To Hold Object?

mukcl · #1 14-Oct-2003, 17:43

Hi everyone!
I have some Lab exercises to do, and well, simply i am stuck.
Can i have some help getting me started, understanding all this? thanx!

I have a Transaction class;

-----------------------------------------------------------------

CPP / C++ / C Code:

class Transaction
{
private:
   int trackingId;
   string hub;
   string transDate;
   String transTime;
   int route;
   int driver;
   string status;
public:
   Transaction (const int tid, const string& h, const string &td, const &tt, const int r, const int d, const string &s)
   {
         // complete the constructor...
   }
};

-----------------------------------------------------------------

i have to complete the constructor, i am not sure how to approach this...

the other part to my exercise is to create 20 sample records (with code provided from this file "http://www.vtr.net/~mwb/c++/part21b.cpp" )and store them in a vector named trans (not necessary to read the data from a text file)

how do i start???? gracias amigos!

Garth Farley · #2 15-Oct-2003, 03:16

To complete the constructor, you simply assign the arguments that are sent to the Transaction() function/constructor, to the private members of the class. I.e.

A constructor is run to set up the class - so that the other functions have something to work with. All the objects variables would be undefined, unless there's a constructor to set them up.

Here's one or 2 to get you started:

CPP / C++ / C Code:

Transaction (const int tid, const string& h, const string &td, const string &tt, const int r, const int d, const string &s)
 {
 // complete the constructor...
 trackingId = tid;   //simply fill in the variables - check them if necessary
 hub = h;   //see if this works!
 //etc...
 }

Question 2: A vector is a dynamic array. Normal arrays have a fixed size - vectors can expand as required. Vectors are part of the C++ STL (Standard Template Library) - and are easy to use.

You create a vector and add a Transaction as follows:

CPP / C++ / C Code:

vector<Transaction> trans();  //empty

trans.push_back(Transaction(1365,"Norwich","20030901","1200",12,005,"Nobody present")); //adds one Transaction.

and you can keep doing that.

GF

mukcl · #3 15-Oct-2003, 03:47

thanks for the definitions, i had them kinda mixed up....its getting clearer!

is this ok then?

CPP / C++ / C Code:

public:
	Transaction (const int tid, const string& h, const string &td, const string &tt, const int r, constint d, const string &s)

	{
		//constructor

		trackingId = tid;
		hub = h;
		transDate = td
    transTime = tt
		route = r
		driver = d
		status = s


	}

the vector...do i create a new class? or do i enter in the same transaction class??

i am not sure how to test this either? to make sure i am doing ok..

thanks again GF.

Garth Farley · #4 15-Oct-2003, 09:03

You're forgetting your semicolons - the compiler will tell you that anyway.

The vector class is made for you already. Just include <vector> and use away. You have the Transation class coded yourself, then you pass it to the vector as I've mentioned above.

I suggest you look up some books on C++ to get comfortable with the syntax.

GF

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