Tokenize a line with strtok & reverse line out..

Any Help would be appreciated... I have been taking the time to search the WWW for examples... And have found several good once but there not useing TOKEN....


AnyWay,, Here is what it is supposed to happen....

The user inputs a line of text,, tokenizes the line with the "strtok" function and should output the line of text in reverse order....

Cant seem to get passed some error on the back end...

Code:

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>


int _tmain(int argc, _TCHAR* argv[])
{
	char string[100];
	char *tokenPtr;
	char *reverse[100];
	int i;	/* counter */

	
	printf( "Enter a line of text; ");
	scanf(string);
	printf( "\n" );


	tokenPtr = strtok(string, " " );
	


	while(tokenPtr != NULL)
	{	
		for ( i = 0; i < 100; i++)
		{
			reverse [i] = tokenPtr;
		}

		tokenPtr = strtok(NULL, " " );	/* get next token */

	}

		for ( i = 100; i > 0; i--)
		{
			printf("%s ", reverse[i]);
		}

	

	getch();

	return 0;

Reverse order, meaning what?

"hello world" = "world" "hello"
"hello world" = "dlrow olleh"

Let's assume the former. It's easy with recursion. If you don't want to use recursion, then you need to keep a list of all the segments that you're getting (how about an array of pointers to characters).

Looking at your above code, your last loop shouldn't start at 100. It should start at whatever it was at the end of the first loop.


Quzah.

I need to set up a "strcpy"..... I'm almost there just cant seem
to get this to work... Also you stated "I needed more space"...
I believe you speaking to my array size... but not sure...

AnyOne got any more suggestions... I'm still working it....

Code:

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>


int _tmain(int argc, _TCHAR* argv[])
{
    char string[30] = "I need to see this in reverse"; /* initialize char array */
    char *revrseStrng[30];        /* create char array revrseStrng */
    char *tokenPtr;
    int i;    /* counter */


       /* copy contents of string into revrseStrn 
        printf( "%s%s\n%s%s\n", 
        "The string in array x is: ", string,
        "The string in array y is: ", strcpy( revrseStrng, string ) ); 
        */


    

    tokenPtr = strtok(string, " " );

    strcpy( *revrseStrng, string );
    


    while(tokenPtr != NULL)
    {    
        for ( i = 0; i < 30; i++)
        {
            revrseStrng[i] = tokenPtr;
        }

        tokenPtr = strtok(NULL, " " );    /* get next token */

    }

        for ( i = 30; i > 0; i--)
        {
            printf("%s ", revrseStrng[i]);
        }

    

    getch();

    return 0;
}

Originally Posted by MAV_DevWantB

Also you stated "I needed more space"...
I believe you speaking to my array size... but not sure...

Considering that nowhere in my post do I mention anything about space, I too am "not sure". In this case, I'm not sure who you think you're replying to.


Quzah.

Mr. quzah,,,

Please except my apology with the last thread... I am new to these forums and am trying my best to hang out with the big dogs and hoping not to step into my dung...

I have been attempting to understand how to use strtok successfully,, I do get the just of it... but just having problems...

I honestly thought that "(how about an array of pointers to characters)." was a good idea for the strcpy... Im still fuzzy will keep reading and searching WWW...


thnks,

Well you already have the array of character pointers, so you're on the right track. You do need to be allocating space though for each token chunk. Something like:

Code:

x = 0; /* spot to start in your array */
p = strtok( this, " " ); /* your first strtok */
do
{
    if( p )
    {
        words[ x ] = malloc( strlen( p ) + 1 );
        strcpy( words[ x ], p );
        x++;
        p = strtok( NULL, " " );
    }
}
while( p && x < SOMESIZE );

Something similar should work.


Quzah.

Originally Posted by MAV_DevWantB

Mr. quzah,,,

Please except my apology with the last thread... I am new to these forums and am trying my best to hang out with the big dogs and hoping not to step into my dung...

But you still haven't answered quzah's question about what you mean be reverse line out, as in

"hello world" -> "world hello" , or
"hello world" -> "olleh dlrow" , or
"hello world" -> "dlrow olleh"

Originally Posted by MAV_DevWantB

I have been attempting to understand how to use strtok successfully,, I do get the just of it... but just having problems...

I honestly thought that "(how about an array of pointers to characters)." was a good idea for the strcpy... Im still fuzzy will keep reading and searching WWW...


thnks,

You would have had the solution by now if you had given a straightforward reply to quzah instead of goin' around in circles.

Thnks itcbitc you are correct I have not confirmed the requested output on my line of text....

Per your examples this is what the output should be:

"hello world" -> "dlrow olleh"


Sorry to not comfirm,,,, hope to be more clear on future postings as I can see I will need more exposure to the forums to truly evolve with these projects...

I have gotten a bit further with the help of some kind souls on the WWW... So far all that is left is to print out the token[i] in reverse order....

Not sure why it is not working... Any input would be appreciated.. I think the token seems to be throwing me off..........

Code:

#include "stdafx.h"
#include <stdio.h>
#include <string.h>
#include <conio.h>


int _tmain(int argc, _TCHAR* argv[])
{
    char line[30] = "I need to see this in reverse"; 
    char *tokens[15];
    int max_tokens = sizeof(tokens)/sizeof(tokens[0]);
    char *token_ptr;
    int i;


    printf("Original line of text: <%s>\n\n", line);

    token_ptr = strtok(line, " \t\n\n");	/* any whitespace */

    for (i = 0; i < max_tokens && token_ptr != NULL; i++) 
	{
        tokens[i] = token_ptr;
        printf("tokens[%d]: <%s>\n", i, tokens[i]);
        token_ptr = strtok(NULL, " ");
    }

    printf("\nNumber of tokens = %d\n\n", i);

		/* Now just print out tokens[i] starting with 
		index equal to i-1 and going down to zero */

	printf("\n===========================\n");
	printf("===========================\n\n");
	printf("The line of text in revers:\n\n");


	/* ???????????????????????????????????????????? */
	/* ???????????????????????????????????????????? */

	/* CANT SEEM TO GET THE LOOP BELOW TO WORK */


 
               while ( token_ptr != NULL )
	{
		for ( i = -1; i >= 0; i--)
		{
			/*line += *tokens[i];*/

			printf("%s ", tokens[i]);
		}
	}

			/*printf("%s ", tokens[i]);*/



	getch();

	return 0;
}

If your token is whitespace, all you are doing is chopping 'words' up. You would need to call a function to reverse the contents of each word, and then to print those words in the reverse order you got them.

Code:

while( ... )
    get a word
    reverse that word
    count++

for count, count > -1; count--
    print word
    print space

But really, if all you are doing is printing the entire thing in the reverse order you get it, I'm not sure why you need strtok, other than just as a learning exercise. It seems a poor choice for this sort of task.


Quzah.