NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c++-part1/9733

Text File | 1996-08-05 | 4.3 KB | 183 lines

Path: newsfeed.internetmci.com!panix!usenet
From: [e-mail] (Amy Weintraub)
Newsgroups: comp.lang.c++
Subject: Re: need help with linklists
Date: 4 Mar 1996 03:47:29 GMT
Organization: PANIX Public Access Internet and Unix, NYC
Message-ID: <4hdp4h$[e-mail]>
References: <4hd3qn$[e-mail]>
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In article <4hd3qn$[e-mail]>, [e-mail] says...
>
>
>
>does anyone have a simple code that does a linklist??

>thanks
>edward
>
> [e-mail]
>

Edward,

I just wrote this simple program in C that uses a linked list. The program reads a file or
keyboard input from stdin and keeps track of how many times each word occurs then prints a
report one word per line saying how many times each word occurred.  Each word goes in a
node.  It probably isn't fully optimized, I'm only a second semester C student.  But, it
works, and it is simple.  I hope this helps.

/* wclist.c -- reads a file or keyboard input from stdin and keeps
 * track of how many times each word occurs
 * then prints a report one word per line
 * Amy Weintraub 2/1/96 - Data Structures homework 2 */

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

int main(int argc, char *argv[])
{
    char *currword = NULL;    /* pointer to current word */
    struct node *head = NULL;    /* set empty list to point to NULL */
    /* get a word and put it in a node */
    while((currword = getword()) != NULL)  {
        findlink(&head, currword);
    }

    /* print list - should print words with number of occurrences */
    printlist(head);

    return 0;
}
/* wc.c -- gets a word from stdin put it in a buffer and return
 * NULL when done
 * getword()
 * Amy Weintraub DS hw3 */

#include    <stdio.h>
#include    <stdlib.h>
#include    "wclist.h"

#define        TRUE     1
#define        FALSE    0
char * getword()
{
    char c;
    char wordbuf[MAXWORD];
    int wordflag = FALSE;    /* TRUE when in a word */
    int i = 0;    /* index for wordbuf */

    while((c = getchar()) != EOF)  {
        if(c != '\n' && c != ' ' && c != '\t' && wordflag == FALSE){
            wordflag = TRUE;    /* start new word */
            /* maybe add char checking for punctuation */
            *(wordbuf + i) = c;    /* fill wordbuf with chars */
            i++;
        }

        else if(c != '\n' && c != ' ' && c != '\t' &&
                wordflag == TRUE){
            *(wordbuf + i) =c;
            i++;
        }

        if((c == ' ' || c == '\n' || c == '\t') &&
                wordflag == TRUE)  {

            wordflag = FALSE;    /* end of word */
            *(wordbuf + i) = '\0'; /* null term array */

            /* return to main() to link it in */
            return wordbuf;    /* returns local var */
        }
    }
    return NULL;     /* to show EOF reached by getword from stdin */
}

/* wclinked.c -- functions for linked list
 * printlist(), errorfunc(), findlink(),
 * Amy Weintraub Data Structures */

#include    <stdio.h>
#include    <stdlib.h>
#include    <string.h>
#include    "wclist.h"
/* printlist: visit each node in list and print it out */
void printlist(struct node *head)
{
    struct node *pnode = head;

    while(pnode)  {
        printf("%6d ", pnode->count);
        printf("%s\n", pnode->data);
        pnode = pnode->next;
    }
}
/*************************************************************/
/* error function:  prints message and exits program */
void errorfunc(char *s)
{
    fprintf(stderr, "%s", s);
    exit(1);
}
/*************************************************************/
void findlink(struct node **head, char *word)
{
    struct node *prev = *head;
    struct node *curr = *head;
    struct node *n;
    int cmpval = -1;

    while(curr && (cmpval = strcmp(curr->data, word)) < 0) {
        prev = curr;
        curr = curr->next;
    }

    /* if a match is found */
    if(cmpval == 0)
        curr->count++;

    /* no node exists so make one */
    else  {
        if((n = (struct node *)malloc(sizeof(*n))) == NULL)
            errorfunc("Exhauted Memory");
        n->count = 1;
        n->data = strdup(word);
        /* beginning? */
        if((*head == NULL) || (*head == curr))  {
            n->next =curr;
            *head = n;
        }

        /* insertion in middle or end */
        else  {
            n->next = curr;
            prev->next = n;
        }
    }
}

/* wclist.h -- header for ll ds homework 2
 * Amy Weintraub */

#define    MAXWORD        254    /* max line length in C */
struct node {
    char *data;
    int count;            /* number of times word occurs */
    struct node *next;
};
extern void errorfunc(char *s);
extern void printlist(struct node *head);
extern void findlink(struct node **head, char *word);
extern char * getword();