Question

I am having trouble with the strtok function. I keep getting a ‘bus error.’ I wrote a function to return all the words within a line. Could somebody please point out my error?

NOTE: I am used to higher level languages

void extract_words(char tokens[WORD_MAX][WORD_LEN], char* line, int* sizePtr)
{
  printf("in extract words");   //for debugging

  char* chPtr = NULL;
  chPtr = strtok(line, " ");

  int size = 1;                             //words has one element
  while(chPtr != NULL) 
  {  
     strcpy(tokens[size++], chPtr);
     chPtr = strtok(NULL, " ");               //continue to tokenize the string
  }
  *sizePtr = size;
}

Thanks in advance!

Answer 1

strtok modifies the string you pass to it, so it can’t be a string literal. You should be able to do something like this:

void extract_words(char tokens[WORD_MAX][WORD_LEN], const char* line_arg, int* sizePtr)
{
  char line[(WORD_LEN+1)*WORD_MAX];
  char* chPtr = NULL;
  int size = 0;

  strcpy(line,line_arg);
  printf("in extract words");   //for debugging


  chPtr = strtok(line, " ");

  while(chPtr != NULL) 
  {  
     strcpy(tokens[size++], chPtr);
     chPtr = strtok(NULL, " ");               //continue to tokenize the string
  }
  *sizePtr = size;
}

Note that I also initialized size to zero, since array indices start at zero.