sem5-problem2

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define MAX_WORD_LEN 100
#define HASH_SIZE 101

struct nlist {
    struct nlist *next;
    char *word;
    int count;
};

static struct nlist *hashTable[HASH_SIZE];

unsigned hash(char *s) {
    unsigned hashval;
    for (hashval = 0; *s != '\0'; s++)
        hashval = *s + 31 * hashval;
    return hashval % HASH_SIZE;
}

struct nlist *search(char *s) {
    struct nlist *np;
    for (np = hashTable[hash(s)]; np != NULL; np = np->next)
        if (strcmp(s, np->word) == 0)
            return np;
    return NULL;
}

struct nlist *add(char *word) {
    struct nlist *np;
    unsigned hashval;
    if ((np = search(word)) == NULL) {
        np = (struct nlist *) malloc(sizeof(*np));
        if (np == NULL || (np->word = strdup(word)) == NULL)
            return NULL;
        hashval = hash(word);
        np->count = 1;
        np->next = hashTable[hashval];
        hashTable[hashval] = np;
    }
    else
        np->count++;
    return np;
}

int main()
{
    int i;
    for (i = 0; i < HASH_SIZE; i++)
        hashTable[i] = NULL;
    char fileword[100];
    printf("Enter file name: ");
    scanf("%s", fileword);
    FILE *f = fopen(fileword, "r");

    char word[MAX_WORD_LEN], c;
    i = 0;
    do
    {
        c = fgetc(f);
        if (isalpha(c) || isdigit(c))
            word[i++] = c;
        else if (i != 0)
        {
            word[i] = '\0';
            i = 0;
            add(word);
        }
    }
    while (c != EOF);

    struct nlist *np;
    for (i = 0; i < HASH_SIZE; i++)
    {
        np = hashTable[i];
        while (np != NULL)
        {
            printf("%5d\t%s\n", np->count, np->word);
            np = np->next;
        }
    }

    fclose(f);
    return 0;
}