Eliminating duplicate words in random sentences

[sydney25]

In the following code I am outputting a sentence in the form:

"The <noun><verb> the <noun>."

The user enters 10 verbs and 10 nouns.

I use rand and srand to generate random sentences, but I can't use the same
noun twice in the same sentence.

Can someone tell me how to go about doing this?

Should I use a for loop and a temp variable?

How do I distinguish between one noun and the other?

srand(time(NULL)); // Seed rand()

char sentence[maxSentence+1] = "";// Initialize sentence to null string.

//sentence output in the format "The <noun><verb> the <noun>."

for (int k = 0; k < numSentences; k++)
{
strcat(sentence,upperThe); // The
strcat(sentence,space); // (space)
strcat(sentence, noun[(rand()%numWords)]->getNoun()); // random noun
strcat(sentence,space); // (space)
strcat(sentence, verb[(rand()%numWords)]->getVerb()); // random verb
strcat(sentence,space); // (space)
strcat(sentence,lowerThe); // the
strcat(sentence,space); // (space)
strcat(sentence, noun[(rand()%numWords)]->getNoun()); // random noun
strcat(sentence,period); // (period)

cout << sentence << endl;

sentence[0] = '\0'; // Reset sentence to null string for next iteration.
}

[JMS]

This is not the most efficient code and but if the nouns you're working with get's bigger and bigger it gets better. An alternative would keep track of the random number and then if the strstr found a match you could then loop on the random number generator until you found a different one...

Anyway.. this works but will probable make you wait a couple of nano secons longer for your result....

srand(time(NULL)); // Seed rand()

char sentence[maxSentence+1] = "";// Initialize sentence to null string.

//sentence output in the format "The <noun><verb> the <noun>."

for (int k = 0; k < numSentences; k++)
{
strcat(sentence,upperThe); // The
strcat(sentence,space); // (space)
strcat(sentence, noun[(rand()%numWords)]->getNoun()); // random noun
strcat(sentence,space); // (space)
strcat(sentence, verb[(rand()%numWords)]->getVerb()); // random verb
strcat(sentence,space); // (space)
strcat(sentence,lowerThe); // the
strcat(sentence,space); // (space)

// New Code
int iRandom = (rand()%numWords);
for( ; ; )          // infinite loop;  while(TRUE) will work too
{
     if(!strstr( sentence, noun[iRandom]->getNoun())
     {
           // new noun is not part of the sentence
            strcat(sentence, noun[iRandom]->getNoun()); 

           // we added our sencond noun so break out of the infinite loop
            break;
    }
    else
    {
          // new noun already in the sentence so pick another one
           iRandom = (rand()%numWords);
    }
}

// end New Code

strcat(sentence,period); // (period)
cout << sentence << endl;

//   sentence[0] = '\0'; // Reset sentence to null string for next 

// better to zap it all the way
memset( sentence, '\0', sizeof(sentence));    // resets the entire string rather than the first character

iteration.

[sydney25]

JMS thanks for the help.

The program now outputs sentences like:

The dog fly the chaircat.

It looks like the nouns are not repeating, but an extra noun is being added to the end of the sentence. In this case cat.

[JMS]

Have you walked through your code to figure out where that is happenning?

I would check the getNoun() class member first....

Is this double noun behavior happenning every time or most of the time or just some time? If it's not happenning all the time I would make sure that I'm using "memset" on the sentence buffer before every generation.

I would also check this line out..

strcat(sentence,period); // (period)

make sure period isn't set to something whacky like "cat." some of the time..

Another way to debug your code if you can't get the debugger working right is to print out intermediate output to the screen to make sure you're doing what you think you're doing.

good luck.

[sydney25]

JMS thanks again.

Your code produces a new random noun that does not duplicate the first noun. It prints a new noun for all sentences, but still prints the old one before it (i.e. catdog - dog being the new noun).

My code seems O.K.

Here is the line for the ending period.

const char period[] = ".";		// Period

[JMS]

int iRandom = (rand()%numWords);
for( ; ; )          // infinite loop;  while(TRUE) will work too
{
     if(!strstr( sentence, noun[iRandom]->getNoun())
     {
           // new noun is not part of the sentence
            strcat(sentence, noun[iRandom]->getNoun()); 

           // we added our sencond noun so break out of the infinite loop
            break;
    }
    else
    {
          // new noun already in the sentence so pick another one
           iRandom = (rand()%numWords);
    }
}

Sidney,

"My code" is calling your code. This is not to say that you're code is wrong since I don't have your code I can't make that judgement. I would suggest that you debug "your code" and "My code" by 1) stepping through the debugger. 2) writing intermediate values to screen.

The code above will call the line

            strcat(sentence, noun[iRandom]->getNoun());

only once and that is the only line which is concatinationg a noun onto your sentence.

Now be sure you copied "My code" right and make sure that strcat line only apeares once in the code you're running.

I would also call the memset just after your definition rather than merely setting the first byte to '\0'.

char sentence[maxSentence+1] = "";// Initialize sentence to null string.

memset( sentence, '\0', sizeof(sentence));

Good luck and post again once you've narrowed down the problem.

[JMS]

Post the code for the function

getNoun()

I want to look in there to see what it's doing. Did you write this or did your teacher?

[sydney25]

I wrote the code I have so far. I've had some help, but most of it is mine. Here is the code:

2 classes Verb and Noun:

#ifndef problem3_H
#define problem3_H


class Verb
{
public:
    Verb( );
    char* getVerb();

private:
    char theVerb[20] ;

} ;

class Noun
{
public:
    Noun( );
	char* getNoun();

private:
    char theNoun[20] ;
    
} ;

#endif

Here are the functions:

#include <iostream>

using namespace std;

#include "problem3.h"

Verb::Verb( )
{
    cin >> theVerb ;
}


Noun::Noun( )
{
    cin >> theNoun ;
}

char* Noun::getNoun()
{
return theNoun;
}

char* Verb::getVerb()
{
return theVerb;
}

[JMS]

I can take a look at it if you'd like. But you'll need to zip up the project and attach it to the thread.

I've got three files now I need the code where and how you load it.. also need any txt files if you use those..

[sydney25]

JMS, thanks for all of your time and help.

I tried a slightly different approach. The following code works:

int rand_noun1;
	  int rand_verb1;
      int rand_noun2;

  for (int k = 0; k < numSentences; k++)
  {
	  rand_noun1 = rand()%numWords;
	  rand_verb1 = rand()%numWords;
      rand_noun2 = rand()%numWords;

      while(rand_noun1 == rand_noun2) 
	  {
      rand_noun2 = rand()%numWords;
	  }
    strcat(sentence,upperThe);							  // The
	strcat(sentence,space);								  // (space)
	strcat(sentence, noun[rand_noun1]->getNoun()); // random noun
	strcat(sentence,space);								  // (space)
    strcat(sentence, verb[rand_verb1]->getVerb()); // random verb
    strcat(sentence,space);								  // (space)
	strcat(sentence,lowerThe);							  // the
	strcat(sentence,space);								  // (space)
	strcat(sentence, noun[rand_noun2]->getNoun()); // random noun
    strcat(sentence,period);							  // (period)

    cout << sentence << endl;

    sentence[0] = '\0';			 // Reset sentence to null string for next 
iteration.

[Gorgor]

They're gettin' a lil' needlessly complex here.

Assuming numWords is > 1:

int firstNounIndex = rand() % numWords;
int secondNounIndex = 0;

while ((secondNounIndex = rand() % numWords) == firstNounIndex)
     ;

...then assemble your sentence.

If tighter looking code is important (some pedantics wrongfully disdain assignments in conditional expressions because they once stubbed their toe when they were green), do this:

int firstNounIndex = rand() % numWords;
int secondNounIndex = rand() % numWords;

while (secondNounIndex == firstNounIndex)
     secondNounIndex = rand() % numWords;

You can alternatively initialize secondNounIndex to what firstNounIndex is if you are really pedantic^H^H^H^H^H^H^H^H a fussbudget about getting rid of one extra function call:

int firstNounIndex = rand() % numWords;
int secondNounIndex = firstNounIndex;

while (secondNounIndex == firstNounIndex)
     secondNounIndex = rand() % numWords;