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Removing stl features from a program

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Join Date: Oct 2009

Posts: 8

Reputation: jmoran19 is an unknown quantity at this point

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jmoran19

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Removing stl features from a program

Nov 5th, 2009

Hi guys, anyone familiar with the Markov Chain Algorithm? I've got an assignment to take the code from a C++ implementation and remove any stl features like deques and maps, but continue to use strings as my main object type. I've based my changes around a C version of the code, which really just needs to be adapted to use C++ strings instead of C char arrays.

The place I'm running into trouble is trying to initialize all my strings with the "non-word" value

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C++ Syntax (Toggle Plain Text)

"\n"

. Here's the relevant code:

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 C++ Syntax (Toggle Plain Text) 
...
const char NONWORD[] = "\n";
...
int main(void)
{
	int i, nwords = MAXGEN;
	string *prefix[NPREF];	// current input prefix
 
	srand(time(NULL));
	for (int i = 0; i < NPREF; i++)
            hashadd(prefix, NONWORD);
	hashbuild(prefix, cin);
	hashadd(prefix, NONWORD);
	hashgenerate(nwords);
	return 0;
}
...
void hashadd(string *prefix[NPREF], string *suffix)
{
    State *sp;
    sp = lookup(prefix, 1);
    addsuffix(sp, suffix);
    memmove(prefix, prefix+1, (NPREF-1)*sizeof(prefix[0]));
    prefix[NPREF - 1] = suffix;
}
...
const char NONWORD[] = "\n";
...
int main(void)
{
	int i, nwords = MAXGEN;
	string *prefix[NPREF];	// current input prefix

	srand(time(NULL));
	for (int i = 0; i < NPREF; i++)
            hashadd(prefix, NONWORD);
	hashbuild(prefix, cin);
	hashadd(prefix, NONWORD);
	hashgenerate(nwords);
	return 0;
}
...
void hashadd(string *prefix[NPREF], string *suffix)
{
    State *sp;
    sp = lookup(prefix, 1);
    addsuffix(sp, suffix);
    memmove(prefix, prefix+1, (NPREF-1)*sizeof(prefix[0]));
    prefix[NPREF - 1] = suffix;
}

The error I get when I go to compile the code is
"prob3.cpp:104: error: invalid conversion from `const char' to `std::string*'"
pointing to the body of the for loop in main intended to put "\n" in each field of prefix. I've tried replacing all references to NONWORD with

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"\n"

but I get the same error. Does anyone have a tip to caste or convert newline as a string?

I have a feeling this is just one of several little hurdles, so if anyone wants to see more of my code to try and find a way around this problem, let me know.

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Join Date: Feb 2008

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Reputation: daviddoria is a jewel in the rough

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daviddoria daviddoria is offline

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Practically a Master Poster

Nov 5th, 2009

I don't understand why you would want to remove stl features? They make things MUCH easier...

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Join Date: Oct 2009

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jmoran19

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Nov 5th, 2009

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Originally Posted by daviddoria

I don't understand why you would want to remove stl features? They make things MUCH easier...

It's a homework assignment to prove why it's so useful to have the stl features, while at the same time testing your abilities. Unfortunately, being a transfer student at my school puts you at a disadvantage during some of these more arcane assignments.

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Join Date: Feb 2008

Posts: 638

Reputation: daviddoria is a jewel in the rough

Solved Threads: 46

daviddoria daviddoria is offline

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Practically a Master Poster

Nov 5th, 2009

Is this what you are looking for?

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#include <iostream>
#include <string>
 
int main()
{
  const char NONWORD[] = "\n";
 
  std::string test = NONWORD;
  return 0;
}
#include <iostream>
#include <string>

int main()
{
  const char NONWORD[] = "\n";
    
  std::string test = NONWORD;
  return 0;
}