How to print random numbers from a selected sequence?

Question

I want the program to print randomly one of these numbers:

{1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,6,6,6,6,7,7,7,7,8,8,8,8,9,9,9,9,10,10,10,10}

Instead it prints randomly nonsense numbers

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

int main()
{
  srand( time(NULL) );
  int card;
  int deck[40] = {1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,6,6,6,6,7,7,7,7,8,8,8,8,9,9,9,9,10,10,10,10};
  card = rand()% deck[40];
  printf("%d", card);
  return 0;
}

What can I do? thanks

`card = deck[rand() % 40];` would pick one of the 40 cards from `deck` randomly (ignoring a small bias caused by the naive use of `rand() % N`). — Ian Abbott, Nov 30 '20 at 10:06

score 2 · Answer 1 · answered Nov 30 '20 at 14:16

2

This simple way to do this is

card = deck[rand() % 40]

This way you are picking a 'random' index in the 40 numbers of your array. Even tho with this array you have the same probability on every number.You can change the balance by changing the array.

answered Nov 30 '20 at 14:16

ACoelho

341
1
11

[You don't actually have the same probability on every number unless (RAND_MAX % 40) != 0](https://stackoverflow.com/q/10984974/2166798) – pjs Nov 30 '20 at 17:20

How to print random numbers from a selected sequence?

1 Answers1