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

#define    MAXWORD    50        /* maximum length of a command or word    */#define DICTSIZ 100        /* maximum number of entries in diction.*/char    dict[DICTSIZ][MAXWORD+1];/* storage for a dictionary of words    */int    nwords = 0;        /* number of words in the dictionary    */int    nextin(char *cmd, char *word), initw(), insertw(constchar *word);
int    deletew(constchar *word), lookupw(constchar *word);

int
main(int argc, char argv[])
{
    char    word[MAXWORD+1]; /* space to hold word from input line    */char    cmd;
    int    wrdlen;        /* length of input word            */while (1) {
        wrdlen = nextin(&cmd, word);
        if (wrdlen < 0)
            exit(0);
        switch (cmd) {
        case'I':    /* "initialize" */
            initw();
            printf("Dictionary initialized to empty.\n");
            break;
        case'i':    /* "insert" */
            insertw(word);
            printf("%s inserted.\n",word);
            break;
        case'd':    /* "delete" */if (deletew(word))
                printf("%s deleted.\n",word);
            else
                printf("%s not found.\n",word);
            break;
        case'l':    /* "lookup" */if (lookupw(word))
                printf("%s was found.\n",word);
            else
                printf("%s was not found.\n",word);
            break;
        case'q':    /* quit */
            printf("program quits.\n");
            exit(0);
        default:    /* illegal input */
            printf("command %c invalid.\n", cmd);
            break;
        }
    }
}

/*------------------------------------------------------------------------ * nextin - read a command and (possibly) a word from the next input line *------------------------------------------------------------------------ */int
nextin(char *cmd, char *word)
{
    int    i, ch;

    ch = getc(stdin);
    while (isspace(ch))
        ch = getc(stdin);
    if (ch == EOF)
        return -1;
    *cmd = (char) ch;
    ch = getc(stdin);
    while (isspace(ch))
        ch = getc(stdin);
    if (ch == EOF)
        return -1;
    if (ch == '\n')
        return 0;
    i = 0;
    while (!isspace(ch)) {
        if (++i > MAXWORD) {
            printf("error: word too long.\n");
            exit(1);
        }
        *word++ = ch;
        ch = getc(stdin);
    }
    return i;
}

/*------------------------------------------------------------------------ * initw - initialize the dictionary to contain no words at all *------------------------------------------------------------------------ */int
initw()
{
    nwords = 0;
    return 1;
}

/*------------------------------------------------------------------------ * insertw - insert  a word in the dictionary *------------------------------------------------------------------------ */int
insertw(constchar *word)
{
    strcpy(dict[nwords], word);
    nwords++;
    return nwords;
}

/*------------------------------------------------------------------------ * deletew - delete  a word from the dictionary *------------------------------------------------------------------------ */int
deletew(constchar *word)
{
    int    i;

    for (i=0 ; i<nwords ; i++)
        if (strcmp(word, dict[i]) == 0) {
            nwords--;
            strcpy(dict[i], dict[nwords]);
            return 1;
        }
    return 0;
}

/*------------------------------------------------------------------------ * lookupw - look up a word in the dictionary *------------------------------------------------------------------------ */int
lookupw(constchar *word)
{
    int    i;

    for (i=0 ; i<nwords ; i++)
        if (strcmp(word, dict[i]) == 0)
            return 1;
    return 0;
}