#include <unistd.h>
#include <stdio.h>
#include <sys/wait.h>
#include <stdlib.h>

enum
{
    MUL = 1103515245U,
    INC = 12345U,
    MOD = 2147483648U
};

typedef struct RandomGenerator RandomGenerator;
static int next(RandomGenerator *rr);
static void destroy(RandomGenerator *rr);

typedef struct RandomOperations
{
    int (*next) (RandomGenerator *rr);
    void (*destroy) (RandomGenerator *rr);
} RandomOperations;

static const RandomOperations ops = {&next, &destroy};

typedef struct RandomGenerator
{
    unsigned int current;
    const struct RandomOperations *ops;
} RandomGenerator;


static int next(RandomGenerator *rr)
{
    unsigned int cur = rr->current;
    cur = cur * MUL % MOD + INC % MOD;
    rr->current = cur;
    return cur;
}

static void destroy(RandomGenerator *rr)
{
    if (rr == NULL) {
        return;
    }
    free(rr);
}

RandomGenerator *random_create(int seed)
{
    RandomGenerator *rr = calloc(1, sizeof(*rr));
    if (rr == NULL) {
        return NULL;
    }
    rr->current = seed;
    rr->ops = &ops;
    return rr;
}