void append_word(struct word *tmp_word, int *letter_count, char ch){
    tmp_word->data = realloc(tmp_word->data, 
        sizeof(char)*(*letter_count+1));
    tmp_word->data[*letter_count] = ch;
    *letter_count += 1;
}

void reset_word(struct word *tmp_word, int *letter_count){
    tmp_word->data = malloc(sizeof(char));
    *letter_count = 0;
}

void append_sentence(struct sentence *tmp_sentence, struct word *tmp_word){
    tmp_sentence->data = realloc(tmp_sentence->data, 
        sizeof(struct word)*(tmp_sentence->word_count+1));
    tmp_sentence->data[tmp_sentence->word_count] = *tmp_word;
    tmp_sentence->word_count++;
}

void reset_sentence(struct sentence *tmp_sentence){
    tmp_sentence->data = malloc(sizeof(struct word));
    tmp_sentence->word_count = 0;
}

void append_paragraph(struct paragraph *tmp_paragraph, struct sentence *tmp_sentence){
    tmp_paragraph->data = realloc(tmp_paragraph->data, 
        sizeof(struct sentence)*(tmp_paragraph->sentence_count+1));
    tmp_paragraph->data[tmp_paragraph->sentence_count] = *tmp_sentence;
    tmp_paragraph->sentence_count++;
}

void reset_paragraph(struct paragraph *tmp_paragraph){
    tmp_paragraph->data = malloc(sizeof(struct sentence));
    tmp_paragraph->sentence_count = 0;
}

void append_document(struct document *tmp_document, struct paragraph *tmp_paragraph){
    tmp_document->data = realloc(tmp_document->data, 
        sizeof(struct paragraph)*(tmp_document->paragraph_count+1));
    tmp_document->data[tmp_document->paragraph_count] = *tmp_paragraph;
    tmp_document->paragraph_count++;
}

struct document get_document(char* text) {
    //get length of text
    int text_length = strlen(text);
    
    struct word *tmp_word;
    int letters;
    tmp_word = malloc(sizeof(struct word));
    reset_word(tmp_word, &letters);
    
    struct sentence *tmp_sentence;
    tmp_sentence = malloc(sizeof(struct sentence));
    reset_sentence(tmp_sentence);
    
    struct paragraph *tmp_paragraph;
    tmp_paragraph = malloc(sizeof(struct paragraph));
    reset_paragraph(tmp_paragraph);
    
    struct document *tmp_document;
    tmp_document = malloc(sizeof(struct document));
    tmp_document->paragraph_count = 0;
    tmp_document->data = malloc(sizeof(struct sentence)); //paragraph[0]
    
    
    //iterate over the text
    for(int i=0; i<text_length; i++){ //condense by i<strlen(text)
        char ch = text[i];
        if((ch >= 'a' && ch <= 'z') || 
            (ch >= 'A' && ch <= 'Z')){
            //found letter
            
            //put into word
            append_word(tmp_word, &letters, ch);
        } else {
            //found end of word   
            if(letters>0){     
                //terminate word string
                tmp_word->data[letters] = '\0'; 
                //put word into current sentence     
                append_sentence(tmp_sentence, tmp_word);           
                //clean tmp word
                reset_word(tmp_word, &letters);
            }

            //check for end of sentence or paragraph
            if (ch == ' '){ //is word
            
            } else if (ch == '\n'){ 
                //found end of paragraph
                //put into document
                append_document(tmp_document, tmp_paragraph);
                reset_paragraph(tmp_paragraph);
            }
            else { 
                //found end of sentence
                //put into current paragraph
                append_paragraph(tmp_paragraph, tmp_sentence);
                reset_sentence(tmp_sentence);
            }
        }
    }
    //end of document
    append_document(tmp_document, tmp_paragraph);
    
    return *tmp_document;
}

struct paragraph kth_paragraph(struct document Doc, int k) {
    return Doc.data[k-1];
}

struct sentence kth_sentence_in_mth_paragraph(struct document Doc, int k, int m) { 
    return Doc.data[m-1].data[k-1];
}

struct word kth_word_in_mth_sentence_of_nth_paragraph(struct document Doc, int k, int m, int n) {
    return Doc.data[n-1].data[m-1].data[k-1];
}