Trouble with Tokens

[DarrenY]

*Edited*

Sorry, I found the source of the problem..

[Codeplug]

It's ok to post solutions to your own post. It may help others and others may find additional problems or suggest additional solutions.

gg

[DarrenY]

My humble apologies for removing the codes, Codeplug, I'll take note on that in the future.

Ok, its like this, my initial problem was when I input my date (i.e. 13/2/2005). My expected output was (1322005). However, it came out to be '0000' instead. Here's my piece of code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(){

 char dateInput[16], *p;
 char *tokenPtr;
 int StartDay=0;
 int StartMonth=0;
 int StartYear=0;
 int numFieldStartDate = 0;
 const char delit[] = "/";
 int startDateCounter = 0;


 printf("Enter Start Date: ");
 fgets(dateInput, sizeof(dateInput), stdin);
 if((p=strchr(dateInput, '\n'))!=NULL)
     *p = '\0';

/*Token input*/
 tokenPtr = strtok(dateInput,delit);

 while(tokenPtr!=NULL){

   startDateCounter++;
   numFieldStartDate++;

   switch(startDateCounter){
	case '1' : StartDay = atoi(tokenPtr);
		break;
	case '2' : StartMonth = atoi(tokenPtr);
		break;
	case '3' : StartYear = atoi(tokenPtr);
		break;
   }

   tokenPtr = strtok(NULL, delit);

 }
/*if user inputs the wrong date format*/
   if(numFieldStartDate != 3){
	printf("Invalid format");
	exit(-1);
   }
	
/*Display Tokens*/	 
 printf("\n%d", StartDay);
 printf("%d", StartMonth);
 printf("%d\n", StartYear);

	return 0;
}

Input : 13/2/2005
Expected Output : 1322005
Program Output : 0000

The reason I convert them to integers so that I can compare my dates with other dates later in the program..

So, here's my solution

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(){

 char dateInput[16], *p;
 char *tokenPtr;
 int StartDay=0;
 int StartMonth=0;
 int StartYear=0;
 int numFieldStartDate = 0;
 const char delit[] = "/";
 int startDateCounter = 0;


 printf("Enter Start Date: ");
 fgets(dateInput, sizeof(dateInput), stdin);
 if((p=strchr(dateInput, '\n'))!=NULL)
    *p = '\0';

/*Token input*/
 tokenPtr = strtok(dateInput,delit);

 while(tokenPtr!=NULL){

   startDateCounter++;
   numFieldStartDate++;

/* The problem was here and fixed, 
   I had my inverted commas removed*/
   switch(startDateCounter){
	case 1 : StartDay = atoi(tokenPtr);
		break;
	case 2 : StartMonth = atoi(tokenPtr);
		break;
	case 3 : StartYear = atoi(tokenPtr);
		break;
   }

   tokenPtr = strtok(NULL, delit);

 }
/*if user inputs the wrong date format*/
   if(numFieldStartDate != 3){
	printf("Invalid format");
	exit(-1);
   }
	
/*Display Tokens*/	 
 printf("\n%d", StartDay);
 printf("%d", StartMonth);
 printf("%d\n", StartYear);

	return 0;
}

Is there a better way in dealing with dates? I mean to compare them with other dates.

[Dave_Sinkula]

>Is there a better way in dealing with dates?

For formatted input in general you might want to consider sscanf.

#include <stdio.h>
#include <time.h>

int main(void)
{
   char dateInput[16];
   fputs("Enter Start Date: ", stdout);
   fflush(stdout);
   if ( fgets(dateInput, sizeof(dateInput), stdin) )
   {
      struct tm start = {0};
      if ( sscanf(dateInput, "%d/%d/%d", 
                  &start.tm_mday, &start.tm_mon, &start.tm_year) == 3 )
      {
         printf("%d%d%d\n", start.tm_mday, start.tm_mon, start.tm_year);
      }
   }
   return 0;
}

/* my output
Enter Start Date: 13/2/2005
1322005
*/

>I mean to compare them with other dates.

You may want to look into difftime and others in time.h.

[Codeplug]

Walked away before hitting submit - but here's my post even though it's identical advice:

You could use sscanf() to do a lot of the parsing work for you:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* scanf format specification field to skip date seperators '-' and '/' */
#define SKIP_DATE_SEPS  "%*[-/]"

/* format specification for extracting month, day, year as unsigned ints */
#define EXTRACT_DATE_MDY    "%2u" SKIP_DATE_SEPS "%2u" SKIP_DATE_SEPS "%4u"

#define VALID_MONTH(m)  (((m) >= 1) && ((m) <= 12))
#define VALID_DAY(d)    (((d) >= 1) && ((d) <= 31))
#define VALID_YEAR(y)   ((y) >= 2005)

int main()
{
    char dateInput[16];
    unsigned int month, day, year, converted;

    printf("Enter Start Date: ");

    if (!fgets(dateInput, sizeof(dateInput), stdin))
    {
        fputs("Error getting input", stderr);
        return 1;
    }

    converted = sscanf(dateInput, EXTRACT_DATE_MDY, &month, &day, &year);

    if (converted != 3)
    {
        fputs("Invalid input\n", stderr);
        return 2;
    }
    else if (!VALID_MONTH(month))
    {
        fputs("Invalid month\n", stderr);
        return 3;
    }
    else if (!VALID_DAY(day))
    {
        fputs("Invalid day\n", stderr);
        return 4;
    }
    else if (!VALID_YEAR(year))
    {
        fputs("Invalid year\n", stderr);
        return 5;
    }
    
    printf("[%u-%u-%u]\n", month, day, year);
    
    return 0;
}

I'm no C-input guru, so this can probably be improved. As for comparing dates, just compare the year first, then month, then day.
If you have to deal with hours, minutes, and seconds as well - then using struct tm with the time functions provided by <time.h> may be more appropriate.

gg