/* this is a C program */#include <stdio.h>static char *keywords[] =    {    "asm",    "auto",    "break",    "case",    "char",    "class",    "const",    "continue",    "default",    "delete",    "do",    "double",    "else",    "enum",    "extern",    "float",    "for",    "friend",    "goto",    "if",    "inline",    "int",    "long",    "new",    "operator",    "overload",    "private",    "protected",    "public",    "register",    "return",    "short",    "signed",    "sizeof",    "static",    "struct",    "switch",    "this",    "typedef",    "union",    "unsigned",    "virtual",    "volatile",    "void",    "while"    };#define KW_NUMKEYS (sizeof(keywords)/sizeof(*keywords))unsigned int hashsize = 137;char** kwhash;typedef unsigned short u_short;u_shorthash(cp, len, a, b, c)    unsigned char* cp;    u_short len;    u_short a, b, c;    {    return (((u_short)cp[0]         ) ^            ((u_short)cp[1]     << a) ^            ((u_short)cp[len-1] << b) ^             (len               << c)  ) % hashsize;    }intinsert(cp, a, b, c)    char *cp;    u_short a, b, c;    {    short h;    h = hash(cp, strlen(cp), a, b, c);    if (kwhash[h] != NULL)        {/*        printf("Keyword hash collision: %s, %s\n", kwhash[h], cp);*/        return 0;        }    else        kwhash[h] = cp;    return 1;    }inttry(a, b, c)    short a, b, c;    {    short int i;    int collisions;    collisions = 0;    for (i = 0; i < hashsize; ++i)        kwhash[i] = NULL;    for (i = 0; i < KW_NUMKEYS; ++i)        if (!insert(keywords[i], a, b, c))            ++collisions;    return collisions;    }main(argc, argv)    int argc;    char **argv;    {    int min_collisions;    int min_abc = 0;    short a, b, c;    if (argc > 1) hashsize = atoi(argv[1]);    else        {        printf("usage: %s <hash_size>\n\t<hash_size> should be prime.\n",                argv[0]);        exit(-1);        }    if (hashsize < KW_NUMKEYS)        {        printf("Hash table is too small.\n");        exit(-1);        }    kwhash = (char**) malloc(hashsize * sizeof(char*));    min_collisions = hashsize + 1;    for (a = 0; a <= 10; ++a)        {        for (b = 0; b <= 10; ++b)            {            for (c = 0; c <= 10; ++c)                {                int collisions;                collisions = try(a, b, c);                if (collisions <= min_collisions)                    {                    printf("abc: %03x  Collisions: %2d ",                           ((a<<8)|(b<<4)|c), collisions);                    min_collisions = collisions;                    if (collisions == 0) putchar('*');                    putchar('\n');                    }                }            }        }    }