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problem with strtok()

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Join Date: Aug 2008

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smnadig

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problem with strtok()

Aug 19th, 2008

Hi All,

I am facing a problem with using the function strtok(). Following is just a sample code.
The code below stores the string str delimited by comma into an array.

I want to modify the code below so that array would contain an empty space/new line if a value is missing.

i.e., if str[] = source, desti, string1,,string3 ; then my array should hold an empty space/ new line in place of string2.

Can somebody help me with this?
Thanks in Advance

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <conio.h>
#include <string.h>
 
main() 
{
	char str[] = "source,desti,string1,string2,string3";
	char delims[] = ",";
	char *result = NULL;
	char myArray[10][50],*p;
 
 
	result = strtok( str, delims );
 
	while( result != NULL ) 
	{
		printf( "%s \n", result );
		result = strtok( NULL, delims );
	}
 
       getch();
 
}
#include <stdio.h>
#include <conio.h>
#include <string.h>

main() 
{
	char str[] = "source,desti,string1,string2,string3";
	char delims[] = ",";
	char *result = NULL;
	char myArray[10][50],*p;

	
	result = strtok( str, delims );
	
	while( result != NULL ) 
	{
		printf( "%s \n", result );
		result = strtok( NULL, delims );
	}
	
       getch();

}

Last edited by Ancient Dragon; Aug 19th, 2008 at 2:34 pm. Reason: add code tags

Thanks & Regards

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iamthwee

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Re: problem with strtok()

Aug 19th, 2008

Maybe you could find the length of the string inbetween the commas. If it is zero then fill it with a space or newline.

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Radical Edward Radical Edward is offline

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Re: problem with strtok()

Aug 19th, 2008

strtok ignores empty fields. Edward would recommend using another solution, like strcspn and some method of reading or copying a substring:

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <string.h>
 
int main()
{
  const char *str = "source,desti,string1,,string3";
  const char *delims = ",";
 
  size_t start = 0;
 
  while (str[start] != '\0') {
    size_t end = strcspn(str + start, delims);
 
    printf("%.*s\n", end, str + start);
 
    start += (str[start + end] != '\0') ? end + 1 : end;
  }
}
#include <stdio.h>
#include <string.h>

int main()
{
  const char *str = "source,desti,string1,,string3";
  const char *delims = ",";

  size_t start = 0;

  while (str[start] != '\0') {
    size_t end = strcspn(str + start, delims);

    printf("%.*s\n", end, str + start);

    start += (str[start + end] != '\0') ? end + 1 : end;
  }
}

The benefit of this approach is that you don't modify the original string anymore, so it works with string literals.

If at first you don't succeed, keep on sucking until you do succeed.

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Join Date: Aug 2008

Posts: 11

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smnadig

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Re: problem with strtok()

Aug 20th, 2008

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Originally Posted by Radical Edward

strtok ignores empty fields. Edward would recommend using another solution, like strcspn and some method of reading or copying a substring:
Help with Code Tags

c Syntax (Toggle Plain Text)
#include <stdio.h>
#include <string.h>
 
int main()
{
  const char *str = "source,desti,string1,,string3";
  const char *delims = ",";
 
  size_t start = 0;
 
  while (str[start] != '\0') {
    size_t end = strcspn(str + start, delims);
 
    printf("%.*s\n", end, str + start);
 
    start += (str[start + end] != '\0') ? end + 1 : end;
  }
}
#include <stdio.h> #include <string.h> int main() { const char *str = "source,desti,string1,,string3"; const char *delims = ","; size_t start = 0; while (str[start] != '\0') { size_t end = strcspn(str + start, delims); printf("%.*s\n", end, str + start); start += (str[start + end] != '\0') ? end + 1 : end; } }
The benefit of this approach is that you don't modify the original string anymore, so it works with string literals.