shithub: puzzles

ref: 2206a1aa25f783759cdf2336310357c33823dc21
dir: /misc.c/

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/*
 * misc.c: Miscellaneous helpful functions.
 */

#include <assert.h>
#include <stdlib.h>

#include "puzzles.h"

int rand_upto(int limit)
{
    unsigned long divisor = RAND_MAX / (unsigned)limit;
    unsigned long max = divisor * (unsigned)limit;
    unsigned long n;

    assert(limit > 0);

    do {
        n = rand();
    } while (n >= max);

    n /= divisor;

    return (int)n;
}