What's wrong with my pseudo random number generator?

I am having some trouble with my random number generator. How my program works is that the player is given a set of ninja, each with a stealth score. To progress, a ninja needs to pass a "stealth check". How they pass is a RNG will pull any whole number between 0 and the ninja's stealth score. If the RNG pulls a 0, they fail the check. The problem is, some of the ninjas have a stealth score of 1. This results in them always failing the check. After I isolated and tested the RNG separately, this is still the case. I also noticed it doesn't seem to be able to pull from the stealth score itself. For example, a ninja with a stealth score of 3 never pulls 3, only 0, 1, and 2. So, how do I fix this RNG?

int stealth_check(struct ninja student[4]){
    int stealth_pass;
    int i;
    for(i = 0; i < 4; i++){
        stealth_pass = rand() % student[i].stealth;
        printf("%d\n\n", stealth_pass);
    }
return 0;
}

Can't use random number generator in c++

I have searched if anyone had the same problem but I havent found anything. This is my piece of code:

#ifndef GAME__2_RANDOM_H
#define GAME__2_RANDOM_H


#include <random>
#include <chrono>

class Random {
    std::random_device dev;
    std::mt19937 rng(dev());
    std::uniform_int_distribution<std::mt19937::result_type> dist(1,6);
};


#endif //GAME__2_RANDOM_H

I'm getting these 2 errors:

My IDE is clion with Visual studio compiler as you can see here:

What's wrong and why it is not working?

Random permutation/shuffle but guarantees to change every element

I have a np.ndarray, and I want to use shuffle/permutation, but I also want to make sure that every element position is changed. For example:

>>> arr = [1, 2, 3]
>>> np.random.shuffle(arr)
>>> print(arr)
[1, 3, 2]  # One possible output

Desired output: [3, 2, 1], or any permutation that every element position is changed

Why is Max size of int array lower than Int32.MaxValue? [duplicate]

For some reason if you create an int array of size Int32.MaxValue, it throws an OutOfMemoryException: Array dimensions exceeded supported range.

It seems like the maximum size that an array can be initialized to is Int32.MaxValue - 1048576. 1048576 is 2^20. So only this works:

var maxSizeOfIntArray = Int32.MaxValue - 1048576;
var array = new int[maxSizeOfIntArray];

Does any one know why? Is there a way to create a larger integer array?

PS: I need to use arrays instead of lists because of a Math.Net library that only returns arrays for sets of random numbers that are cryptographically secure pseudo random number generator

Yes I have looked at the other questions linked but they are not correct as those questions say the largest size is Int32.MaxValue which is not the same as what my computer lets me do

Yes, I do know the size of the array will be 8GB, I need to generate a data set of billions of rows in order to test the randomness with the die harder suite of tests

Random image from Oracle database and add link this image

How create random image link (image from Oracle database). I want to when refresh page book- image change and when click image open this book pdf (like library page, i.e.https://ift.tt/1aqIwCr). And i want to know i save image as link or Clob or Blob fileld. Thanks!

Getting consecutive numbers without repetition

From a random sequence of numbers {"1", "2", "3", "4", "5"}, it is asked to determine the number of times that groups of 3 consecutive numbers appear, it means, the number of times that have been generated with the base = c ("1", "2", "3", "4", "5") any of the following groups {"123", "234", "345" }.

# I undertand that I have generate a sample with 5 numbers
a<-c(sample(1:5,5))
a
#I generated the list, as you can see I didn't fix a seed because I know that in every single sequence I will have differents grupos of 3 consecutive numbers, so I should obtain something like this

b<-c(2,4,5,1,3) #this example gives me just one that it would be {2,4,5}
b
#answer expected
1
#Then, I don't know how to obtain the sequence I have tried with permutations and combinations but I don't get it.

Select random non-consecutive dates for every grouped element in R

I am currently trying to select non-consecutive dates for every grouped column.

In other words, I have the below dataframe:

I would like to basically group_by(Site) and then keep only 3 random non-consecutive dates for every grouped Site. For example, if HP37P1B has dates corresponding to 12th March, 13th March, 14th March and 7th March - I need a dataframe (for example) that only has:

HP37P1B 12th March

HP37P1B 14th March

HP37P1B 7th March

So far I have tried a number of stackoverflow posts that use diff(), ave(), and the lubridate package, but I haven't had any success.

EDIT

Based on comments below, I am trying to make this question reproducible

dput(uniqueSiteDate)

structure(list(Site = c("HP37P1B", "HP37P2B", "HP37P4B", "HP4008U", 
"INME03R", "INME03U", "INOA03R", "IPTO04R", "IPTO04U", "IPTO06R", 
"IPTO06U", "OLCAP2B", "OLCAP3B", "OLCAP5B", "PANMP1B", "PANMP2B", 
"PANMP3B", "STIN02R", "STIN02U", "UPMAP1B", "UPMAP3B", "UPMAP4B", 
"UPMAP5B", "UPMAP6B", "VAR210R", "VAR310R", "VAR310U", "VAR410R", 
"VAR410U", "HP36P1B", "HP36P3B", "HP36P4B", "HP4008R", "INBS04R", 
"INBS04U", "SEL107R", "SEL107U", "SEL207R", "SEL207U", "OLV110R", 
"OLV110U", "OLV208R", "OLV208U", "THEN10U", "HP37P1B", "HP37P2B", 
"HP37P4B", "HP4008U", "INME03R", "INME03U", "INOA03R", "IPTO04R", 
"IPTO04U", "IPTO06R", "IPTO06U", "OLCAP2B", "OLCAP3B", "OLCAP5B", 
"PANMP1B", "PANMP2B", "PANMP3B", "STIN02R", "STIN02U", "UPMAP1B", 
"UPMAP3B", "UPMAP4B", "UPMAP5B", "UPMAP6B", "VAR210R", "VAR310R", 
"VAR310U", "VAR410R", "VAR410U", "OLV110R", "OLV110U", "OLV208R", 
"OLV208U", "THEN10U", "HP37P1B", "HP37P2B", "HP37P4B", "HP4008U", 
"INME03R", "INME03U", "INOA03R", "IPTO04R", "IPTO04U", "IPTO06R", 
"IPTO06U", "OLCAP2B", "OLCAP3B", "OLCAP5B", "PANMP1B", "PANMP2B", 
"PANMP3B", "STIN02R", "STIN02U", "UPMAP1B", "UPMAP3B", "UPMAP4B", 
"UPMAP5B", "UPMAP6B", "VAR210R", "VAR310R", "VAR310U", "VAR410R", 
"VAR410U", "OLV110R", "OLV110U", "OLV208R", "OLV208U", "THEN10U", 
"HP37P1B", "HP37P2B", "HP37P4B", "HP4008U", "INME03R", "INME03U", 
"INOA03R", "IPTO04R", "IPTO04U", "IPTO06R", "IPTO06U", "OLCAP2B", 
"OLCAP3B"), Date = structure(c(18333, 18333, 18333, 18333, 18335, 
18335, 18335, 18338, 18335, 18338, 18335, 18333, 18333, 18333, 
18334, 18334, 18334, 18331, 18331, 18331, 18330, 18330, 18330, 
18330, 18332, 18332, 18332, 18332, 18332, 18325, 18325, 18325, 
18325, 18327, 18327, 18327, 18327, 18327, 18328, 18340, 18340, 
18340, 18340, 18340, 18334, 18334, 18334, 18334, 18336, 18336, 
18336, 18339, 18336, 18340, 18336, 18335, 18334, 18334, 18335, 
18335, 18335, 18332, 18332, 18332, 18331, 18331, 18331, 18331, 
18333, 18333, 18333, 18333, 18333, 18341, 18341, 18341, 18341,
18341, 18335, 18335, 18335, 18335, 18383, 18383, 18383, 18384, 
18384, 18384, 18384, 18385, 18385, 18335, 18342, 18342, 18341, 
18383, 18383, 18345, 18349, 18349, 18349, 18349, 18340, 18339, 
18340, 18341, 18339, 18386, 18386, 18348, 18346, 18347, 18328, 
18328, 18328, 18328, 18390, 18389, 18391, 18392, 18392, 18392, 
18392, 18392, 18392), class = "Date")), row.names = c(NA, -125L
), groups = structure(list(Site = c("HP36P1B", "HP36P3B", "HP36P4B", 
"HP37P1B", "HP37P2B", "HP37P4B", "HP4008R", "HP4008U", "INBS04R", 
"INBS04U", "INME03R", "INME03U", "INOA03R", "IPTO04R", "IPTO04U", 
"IPTO06R", "IPTO06U", "OLCAP2B", "OLCAP3B", "OLCAP5B", "OLV110R", 
"OLV110U", "OLV208R", "OLV208U", "PANMP1B", "PANMP2B", "PANMP3B", 
"SEL107R", "SEL107U", "SEL207R", "SEL207U", "STIN02R", "STIN02U", 
"THEN10U", "UPMAP1B", "UPMAP3B", "UPMAP4B", "UPMAP5B", "UPMAP6B", 
"VAR210R", "VAR310R", "VAR310U", "VAR410R", "VAR410U"), .rows = structure(list(
    30L, 31L, 32L, c(1L, 45L, 79L, 113L), c(2L, 46L, 80L, 114L
    ), c(3L, 47L, 81L, 115L), 33L, c(4L, 48L, 82L, 116L), 34L, 
    35L, c(5L, 49L, 83L, 117L), c(6L, 50L, 84L, 118L), c(7L, 
    51L, 85L, 119L), c(8L, 52L, 86L, 120L), c(9L, 53L, 87L, 121L
    ), c(10L, 54L, 88L, 122L), c(11L, 55L, 89L, 123L), c(12L, 
    56L, 90L, 124L), c(13L, 57L, 91L, 125L), c(14L, 58L, 92L), 
    c(40L, 74L, 108L), c(41L, 75L, 109L), c(42L, 76L, 110L), 
    c(43L, 77L, 111L), c(15L, 59L, 93L), c(16L, 60L, 94L), c(17L, 
    61L, 95L), 36L, 37L, 38L, 39L, c(18L, 62L, 96L), c(19L, 63L, 
    97L), c(44L, 78L, 112L), c(20L, 64L, 98L), c(21L, 65L, 99L
    ), c(22L, 66L, 100L), c(23L, 67L, 101L), c(24L, 68L, 102L
    ), c(25L, 69L, 103L), c(26L, 70L, 104L), c(27L, 71L, 105L
    ), c(28L, 72L, 106L), c(29L, 73L, 107L)), ptype = integer(0), class = c("vctrs_list_of", 
"vctrs_vctr", "list"))), row.names = c(NA, -44L), class = c("tbl_df", 
"tbl", "data.frame"), .drop = TRUE), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"))

To answer other questions, sometimes there are more than 3 dates per site, but sometimes there is just 1 date per site. But the idea is to choose n Number of non-consecutive dates given a Site. In other words, if a particular site has 4 dates, I need 3 non-consecutive ones. If a particular site has only 1 date, let's just leave that in.