frequency.c

# include "frequency.h"
# include <stdio.h>
# include <stdlib.h>
# include <string.h>

node *new_node(char c) {
    node *p = (node *) calloc(1, sizeof(node));
    if (p!=NULL){
        p->letter = c;
        p->count = 0;
        p->num_of_ch = 0;
        p->end = FALSE;
    }
    return p;
}

int read() {
    int len = 0;
    int max=0;
    start = new_node('^');
    node *last_n = start;
    node *curr_n = NULL;
    char curr_c = fgetc(stdin);
    while (curr_c != EOF) {
        if (curr_c >= 'a' && curr_c <= 'z') { //small letters
            last_n = add_letter(last_n, curr_c, curr_n);
            len++;
        }
        if (curr_c >= 'A' && curr_c <= 'Z') { //big letters
            curr_c = curr_c + ('a' - 'A');
            last_n = add_letter(last_n, curr_c, curr_n);
            len++;
        }
        if (curr_c == '\n' || curr_c == '\t' || curr_c == ' ') {
            if (len > max) max = len;
            len = 0;
            last_n->end = TRUE;
            last_n->count++;
            last_n = start;
            start->count++; // we read a whole word
        }
        curr_c = fgetc(stdin);
    }
    if (len > max) max = len;
    last_n->end = TRUE;
    last_n->count++;
    return max;
}

node *add_letter(node *last_n, char curr_c, node *curr_n) {
    if (last_n->children[curr_c - 'a'] == NULL) {
        last_n->num_of_ch++;
        curr_n = new_node(curr_c);
        if (curr_n==NULL) {
            free_all(start);
            exit(1);
        }
        last_n->children[curr_c - 'a'] = curr_n;
        return curr_n;
    } else {
        curr_n = last_n->children[curr_c - 'a'];
        return curr_n;
    }
}

void print(node *curr, int i, char *arr) {
    if (curr->end == TRUE && curr->letter!='^') {
        arr[i] = curr->letter;
        arr[i+1] = '\0';
        printf("%s %lu\n",arr, curr->count);
        curr->end = FALSE;
    }
    if (curr->letter!='^') {
        arr[i] = curr->letter;
        arr[i+1]='\0';
    }
    if ((curr!=start&&curr->num_of_ch!=0)||curr==start){
        for (int j = 0; j <=NUM_LETTERS-1; ++j) {
            if (curr->children[j] != NULL) {
                i = (int) strlen(arr);
                print(curr->children[j] ,i,  arr);
                arr[i]='\0';
            }
        }
    }
}

void print_reverse(node *curr, int i, char *arr) {
    if (curr->letter != '^') {
        arr[i] = curr->letter;
        arr[i+1] = '\0';
    }
    if ((curr != start && curr->num_of_ch != 0) || curr == start) {
        for (int j = NUM_LETTERS - 1; j >= 0; --j) {
            if (curr->children[j] != NULL) {
                i = (int) strlen(arr);
                print_reverse(curr->children[j], i, arr);
                arr[i] = '\0';
            }
        }
    }
    i = (int) strlen(arr) - 1;
    if (curr->end == TRUE && curr->letter != '^') {
        arr[i] = curr->letter;
        arr[i + 1] = '\0';
        printf("%s %lu\n", arr, curr->count);
        curr->end = FALSE;
    }
}


void free_all(node *curr) {
    for (int j = 0; j < NUM_LETTERS - 1; ++j) {
        if (curr->children[j] != NULL) {
            free_all(curr->children[j]);
        }
    }
    free(curr);
}

int main(int argc, char **args) {
    int max =read();
    char *arr = (char *) calloc(1,(max+1)* sizeof (char));
    if (arr==NULL) {
        free_all(start);
        exit(1);
    }
    arr[0]='\0';
    if(argc==2&&args[1][0]=='r'){
        print_reverse(start,0, arr);
    }
    else{
        print(start,0, arr);
    }
    print(start,0, arr);
    free_all(start);
    free(arr);
    exit(0);
}