khash-learn.c

/*
 * example for me to learn khash.h library from lh3
 */

#include "khash.h"
#include <stdio.h>

// int keys and char * values
KHASH_MAP_INIT_INT(ihash, char *)

// char * keys and char * values
KHASH_MAP_INIT_STR(chash, char *)

char *strings[3] = {"aa", "bb", "cc"};

int main() {
    int ret, is_missing, i;

    khiter_t key;

    // define a new ihash h
    khash_t(ihash) *h = kh_init(ihash);

    char *val;
    for(i=0; i < 3, val=strings[i]; i++){
        // put the key of 5 into the hash 
        key = kh_put(ihash, h, i, &ret);
        // give it a value
        kh_val(h, key) = val;
    }


    // make sure it's in there.
    for(i = 0; i < 5; i++){
        key = kh_get(ihash, h, i);
        // get the value of each key if it's present.
        if (key != kh_end(h)){
            printf("value at %d: %s\n", i, kh_val(h, key));
        } else {
            printf("%d missing\n", i);
        }
    }

    // delete a key and make sure it's gone
    kh_del(ihash, h, 1);
    key = kh_get(ihash, h, 1);
    printf("should be 1:%d\n", key == kh_end(h));
    
    kh_destroy(ihash, h);





    printf("char * => char *\n");
    // now with another type of hash
    khash_t(chash) *hc = kh_init(chash);

    key = kh_put(chash, hc, "akey", &ret);
    kh_val(hc, key) = "aval";

    key = kh_get(chash, hc, "akey");
    printf("value at akey: %s\n", kh_val(hc, key));

    kh_destroy(chash, hc);

    return 0;
}