Random number with limited deviation from previous value [closed]

I'm trying to generate a random number within range 1 to 20. So let's say I get 10. I would like the next random number to be close to the last random number so say 10.6 or 9.1. How would I give this this new random number a range that is close to the last one?

Current code:

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main()
{
    int min = 1, max = 20;

    srand(time(0));
    printf("The random number is: ");
    int num = (rand() % (min - max));
    printf("%d ", num);
    return 0;
}