how could I find and extract a punctuation from a word of a paragraph text file?

Question

int main()
{
    FILE *fO;

    fO = fopen("random.txt", "r");

    size_t size = 0;
    int len = 0;

    // initialize it for the getline() and strtok()
    char *line = NULL;

    // loop through the file
    node *head = NULL;

    while (getline(&line, &size, fO) != -1) {
        // strip newline
        line[strcspn(line,"\n")] = 0;

        char *word = strtok(line," ");
        char *mark;
    
        while (word != NULL){
            word = strtok(NULL," ");
             
            //why would this part make mark == 44?
            if(ispunct(word[strlen(word)-1]) != 0){
                int w = word[strlen(word)-1];
                itoa(w, mark, 10);
                printf("%s mark\n", mark);
                //i was hoping that it would be punctuation of type const *char
            }
        }
    }

    //free at end
    free(line);

the file is like(for eg):

lorem ipsum,
dolor.
sit amet con,
sec it.

the file has unpredictable numbers of words on each line. I thought I was getting a character with mark = word[strlen(word)-1]. I expected to get a comma or period. Does anyone know why it ended up as an integer of 44?