Thread: Creating a class variable with a string

Let's say I have defined a class in a header file; just the class, no templates involved. I have a program where I'm reading in data in string format. Each string consists of a word, a delimiter, and a variable name. Example:

cajun/mustard

I want to take that string and make it the variable name of that class type. It woule be implemented along the lines of:

Code:

string str;

//read/process string here, get:
str = "mustard";

createName(str);                 //pass string to creator function

When the function is called, I should get the variable:

Class mustard;

Thing is, I'm not supposed to know beforehand what the variable names are, only that I create them as they are read in. It could be mustard, it could be Maynard_James_Keenan, it could even be bazinga.

My problem is, what do I do for createName()? I've looked into the concepts of pairing, Factory implementation, and maps, but I don't think they answer my question. I would greatly appreciate anyone's help.

(P.S. A bonus question for the daring: if I run into the same variable name being read in twice, what steps can I take to make sure that a duplicate variable isn't created? Do I need to add in code, or does the compiler know to watch for multiple variables of the same name?)

essentially, i have a trie header file, a 10mb text file of compiled words and their syntactic labels (formatted like above), and a mission to make reading in the data, storing it, and getting to it as quickly and efficiently as possible. i want to create trie variables for each syntactic label, but there are so many of them, and not only do my references not list all the ones that are used, but declaring every single variable (i counted 35, excluding punctuation, which have their own tries) and assigning specific code to each one seems like the greatest waste of time and overhead imaginable for this scope.

i know it seems like it may not be possible, but i'm just trying to see if i can dynamically create these variables to make my life a bit easier.

Originally Posted by William Putnam

essentially, i have a trie header file, a 10mb text file of compiled words and their syntactic labels (formatted like above), and a mission to make reading in the data, storing it, and getting to it as quickly and efficiently as possible. i want to create trie variables for each syntactic label, but there are so many of them, and not only do my references not list all the ones that are used, but declaring every single variable (i counted 35, excluding punctuation, which have their own tries) and assigning specific code to each one seems like the greatest waste of time and overhead imaginable for this scope.

I didn't know what a trie was until I looked it up at wiki:

Trie - Wikipedia, the free encyclopedia

However, I am familiar with associative arrays and in the case of hardware, content addressable memory.

What is the goal here? Are you trying to search for variable names in order to return words or vice versa, or are you simply trying to search for a specific combination of word and variable name?

It is possible to literally do what you're asking with some interactive languages such as APL (variable names and variables can be dynamically created from strings via "execute" (functions can be dynamically created from matrices), and a search could be performed from a list of variable names (which can be dynamically created by the "quad name list" operator), ... but I don't see what this would accomplish. You'd be stuck with APL's symbol search when trying to actually search for and use one of thousands of variables.

Originally Posted by rcgldr

What is the goal here? Are you trying to search for variable names in order to return words or vice versa, or are you simply trying to search for a specific combination of word and variable name?

In response to your question, my objective is to have the user enter a variable name and get a list of syntactical labels with which it's used. For example, doctor can be considered a noun and a verb, so it would search the trie of each syntactical label, and if it's found in the trie, the syntactical device is listed.

I understand the concerns you may have that this is not the best method. However, I've already been playing with Flexarrays and binary search trees for my data structures class, and I really want to give tries a try. From what I've learned, tries are quick to search, and I'm looking for something that searches fast and efficiently, especially given how much data I'm reading in.

I should've included a bit more context earlier, so I've attached the trie header/cpp file so you can see what it is I'm up against if that helps.
trie.h
trie.cpp