CS Student need help with debugging string program

[nnguyec]

Hi, I'm trying to write a small code for an assignment which the void String Tokenizer will get a line input, and take out those delimiters from the original string. Then pass each string without the delimiters back to the struct.

For an example:
Line in is: Today, Friday 23, is a crazy day.
Delimiters is: " ,." /*space, comma and period/*
The stuct will get total of 7 words: "Today", "Friday", "23", "is" ..... "day".

This is the codes for that little function:

void constructStringTokenizer(struct StringTokenizer* tokenizer, const char line[], const char delimiters[])
{
char* temp;
int i, j, k;
k=0;
for (i =0; i < strlen(line); i++)
{
   if (k == 0)
   temp = malloc (sizeof(char)*MAXLEN+1);
// printf ("%d\n", i);
   for (j = 0; j < 3; j++)
   {
//     printf("Went through one delimiter\n");
       if (line[i]==delimiters[j])
       {
           i++;
           tokenizer->tokens[tokenizer->count] = (char*)malloc(sizeof(char)*(k+1));
           strcpy (tokenizer->tokens[tokenizer->count++],temp);
           strcpy (temp, "");
           k = 0;
           printf ("One string copied\n");
           break;
        }
    }
    temp[k]=line[i];
    k++;
    printf ("%s\n", temp);
}
//	free (temp);
}

I tested each string passed back into the struct, and first 2 strings are fine, but all other strings are really messed up, with weird characters at the end. At the same time, it skipped last 2 words. Is something wrong with my algorithm? Is there a alternate algorithm for doing this?

Thanks.

[Ganon11]

One thing I spotted was that, when you use malloc to set temp, you don't cast it to a char* a.k.a.

temp = (char*)malloc(sizeof(char) * MAXLENGTH + 1)

Also, you only free temp at the end of the function, though it may be possible that temp has a new array allocated to it several times, leaving several blocks of char arrays in memory.

[nnguyec]

Thank you for quick replying. Yeah, I noticed the (char*)malloc error. I thought that since that token in struct Tokenizer is also a (char*), I need that to memory allocate approriately.

Also, I'm using VC++ 6.0, for some reason, it doesn't let me free temp, even at the end. That's why I didn't free temp, I opted that code out using //.

[Ganon11]

Well, I know the new standard is to use new and delete rather than malloc and free, so maybe VC++ is only letting you use delete instead of free...

[nnguyec]

Hi, I had found and fixed the bug. It does everything I want it to do, except one thing. I believe there's an error in allocating the string. I tried to find the error in coding, but no avail. Each string copied into the struct was fine, however, at the end of each string, there are 4 extra 'weird' characters -- which are not suppose to be there. Can you please check my algorithm and codes?

void constructStringTokenizer(struct StringTokenizer* tokenizer, const char line[], const char delimiters[])
{
char* temp;
int i, j, k;
k=0;
temp = malloc (sizeof(char)*MAXLEN+1);
for (i =0; i < strlen(line); i++)
{
    for (j = 0; j < 3; j++)
    {
        if (line[i]==delimiters[j])
        {
           tokenizer->tokens[tokenizer->count] = malloc(sizeof(char)*(k));
           strncpy (tokenizer->tokens[tokenizer->count++],temp, k);
           strcpy (temp, " ");
           k = 0;
           i++;
           break;
        }
    }
if (line[i] == delimiters[0])
i++;
temp[k]=line[i];
k++;
}
free (temp);
}