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How do i generate a random number but exclude some of them?

DAoliHVAR (77)
alright,so i need to generate a random number.
its a number between 1-54
this is a bad explanation of the program feel free to skip
---------------------------------
the program draws cards so thats why its 54
now the thing is,i need the program to draw a specific set of cards,and end when it draws them.
the way it checks if the cards are the ones that i need is because the sum of their value is below 33.
or atleast thats what i thought,turns out you can make the value of 33 with other combos aswell.
--------------------------------------------
so back to the question,i need a random number generated from 1-8,and then from 19-65.
i thought about checking with an if statement,but i dont think that would work since it would check only once or twice,and then go on..
so is there any easier way.
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   srand( time(NULL));
   int CardsRolled[6];
    int sum=34;
    int numb=0;
    while(sum>33){
        sum=0;


        cout<<"\n";

        cout<<numb<<"---";
        for(int i=0;i<6;i++){

            int xRan;
	xRan=rand()%54+1;

this is the part of the code that generates the random number
Chervil (7320)
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#include <iostream>
#include <cstdlib>

using namespace std;

int random(int from, int to)
{
    return from + rand() % (to - from + 1);
}

int main()
{
   // I need a random number generated from 1-8, and then from 19-65.

    cout << random(1, 8)   << endl;
    cout << random(19, 65) << endl;
}
DAoliHVAR (77)
thanks for the code bro,but wouldn't this generate two numbers,one from 1-8
and one from 19-65.
i think i worded the question wrong so its my fault.
i need 1 number to be generated that follows those rules.
booradley60 (896)
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#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;

int random(int from, int to)
{
    return from + rand() % (to - from + 1);
}

int main()
{
    // I need a random number generated from 1-8, and then from 19-65.
    srand(time(nullptr));
    int myRand;

    if (random(0,1))
    {
        myRand = random(1, 8);
    }
    else
    {
        myRand = random(19, 65);
    }

    cout << myRand << endl;
}


:)
EDIT: seeded the rng
Last edited on
DAoliHVAR (77)
alright thanks to both of you i think i know what to do now
booradley60 (896)
The method I showed probably isn't what you want. Since one of those ranges is larger than the other, the fact that either range is decided upon by coin-toss practically means that each number in the smaller range will appear more frequently than any number in the larger range.
Duthomhas (13104)
Argh. Two suggestions:

1. Split the range. (1-8 == 9 cards) + (19-65 == 47 cards) = 56 cards.

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int c = get_random_number_in( 1, 56 );
if (c > 8) c += 10; // 9-->19, etc.

2. Throw away invalid numbers

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int c;
do {
  c = get_random_number_in( 1, 65 );
} while ((c > 8) && (c < 19));

Hope this helps.
Computergeek01 (5613)
What CARD game are we emulating here OP? Because I have a feeling that you're going about this all wrong. Random number generation is not your solution to this.

You're talking about a standard deck of cards, 54 cards so that's 40 number cards, 12 faces and 2 jokers correct? Since you can only draw a card once, you need to prevent duplicate entries. Now you could keep building on the random number generation like you asked for until it becomes a complete mess of code. Or you could populate a vector with the values of each card in the deck, then apply std::random_shuffle() to that vector and pop the results off the top of the array just like you do with a real deck of cards in meat space. I can post some code if you want, but the code I had in mind to copy and paste into here is basically me screwing around with Lambda's so I'd have to clean it up and make it readable first.
DAoliHVAR (77)
@booradley yes,the method you gave me worked,but what you said happened,and thats why the program didn't work correctly
thanks for the reply computer geek.
the card game i am emulating is called makao where i live.'
the rules are unimportant,what is important for this is that,the A cards and the 8 cards are cards used for skipping a player.so if i throw and A spade for example,the next player loses his turn.
this program is just drawing cards untill a full hand of cards that skip is drawn(one hand consists of 6 cards).
and each time a hand is drawn the deck is reset.
also,i have VERY limited experience in c++,and i sort of challenged myself to write this program no matter how bad,unoptimized or stupid it is.
i have no idea how to use half of the things you said.
i will post the code to my program here,its long but 90% of it is just repetition i could have probably skipped if i had more experience.
the program needs to end only when a hand consists of only 8ts and Aces
and not any other number.i think i messed up in the checking of the hand part so it doesn't work now.
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#include <iostream>
#include <ctime>
#include <stdlib.h>
#include <cmath>
using namespace std;

int main(){
    srand( time(NULL));
   int CardsRolled[6];
    int sum=34;
    int numb=0;
    while(sum>33||CardsRolled[0,1,2,3,4,5]==9||10||11||12||13||14||15||16||17||18){
        sum=0;


        cout<<"\n";

        cout<<numb<<"---";
        for(int i=0;i<6;i++){




            int xRan;
	xRan=rand()%54+1;
//this checks if the number has been rolled before and if it has gets a new 
//one,it isn't 100% though
    if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    } if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }if(xRan==CardsRolled[0]||xRan==CardsRolled[1]||xRan==CardsRolled[2]||xRan==CardsRolled[3]||xRan==CardsRolled[4]||xRan==CardsRolled[5]){
        xRan=rand()%54+1;
    }else{

	switch(xRan){
case 1:
    cout<<"1a,";
    CardsRolled[i]=xRan;
    break;
case 2:
    cout<<"1b,";
    CardsRolled[i]=xRan;
    break;
case 3:
    cout<<"1c,";
    CardsRolled[i]=xRan;
    break;
case 4:
    cout<<"1d,";
    CardsRolled[i]=xRan;
    break;
case 5:
    cout<<"8a,";
    CardsRolled[i]=xRan;
    break;
case 6:
    cout<<"8b,";
    CardsRolled[i]=xRan;
    break;
case 7:
    cout<<"8c,";
    CardsRolled[i]=xRan;
    break;
case 8:
    cout<<"8d,";
    CardsRolled[i]=xRan;
    break;
case 9:
    cout<<"2a,";
    CardsRolled[i]=xRan;
    break;
case 10:
    cout<<"2b,";
    CardsRolled[i]=xRan;
    break;
case 11:
    cout<<"2c,";
    CardsRolled[i]=xRan;
    break;
case 12:
    cout<<"2d,";
    CardsRolled[i]=xRan;
    break;
case 13:
    cout<<"3a,";
    CardsRolled[i]=xRan;
    break;
case 14:
    cout<<"3b,";
    CardsRolled[i]=xRan;
    break;
case 15:
    cout<<"3c,";
    CardsRolled[i]=xRan;
    break;
case 16:
    cout<<"3d,";
    CardsRolled[i]=xRan;
    break;
case 17:
    cout<<"joker,";
    break;
case 18:
    cout<<"4a,";
    CardsRolled[i]=xRan;
    break;
case 19:
    cout<<"4b,";
    CardsRolled[i]=xRan;
    break;

case 20:
    cout<<"4c,";
    CardsRolled[i]=xRan;
    break;
case 21:
    cout<<"4d,";
    CardsRolled[i]=xRan;
    break;
case 22:
    cout<<"5a,";
    CardsRolled[i]=xRan;
    break;
case 23:
    cout<<"5b,";
    CardsRolled[i]=xRan;
    break;
case 24:
    cout<<"5c,";
    CardsRolled[i]=xRan;
    break;
case 25:
    cout<<"5d,";
    CardsRolled[i]=xRan;
    break;
case 26:
    cout<<"6a,";
    CardsRolled[i]=xRan;
    break;
case 27:
    cout<<"6b,";
    CardsRolled[i]=xRan;
    break;
case 28:
    cout<<"6c,";
    CardsRolled[i]=xRan;
    break;
case 29:
    cout<<"6d,";
    CardsRolled[i]=xRan;
    break;
case 30:
    cout<<"7a,";
    CardsRolled[i]=xRan;
    break;
case 31:
    cout<<"7b,";
    CardsRolled[i]=xRan;
    break;
case 32:
    cout<<"7c,";
    CardsRolled[i]=xRan;
    break;
case 33:
    cout<<"7d,";
    CardsRolled[i]=xRan;
    break;
case 34:
    cout<<"Ka,";
    CardsRolled[i]=xRan;
    break;
case 35:
    cout<<"Kb,";
    CardsRolled[i]=xRan;
    break;
case 36:
    cout<<"Kc,";
    CardsRolled[i]=xRan;
    break;
case 37:
    cout<<"Kd,";
    CardsRolled[i]=xRan;
    break;
case 38:
    cout<<"9a,";
    CardsRolled[i]=xRan;
    break;
case 39:
    cout<<"9b,";
    CardsRolled[i]=xRan;
    break;
case 40:
    cout<<"9c,";
    CardsRolled[i]=xRan;
    break;
case 41:
    cout<<"9d,";
    CardsRolled[i]=xRan;
    break;
case 42:
    cout<<"10a,";
    CardsRolled[i]=xRan;
    break;
case 43:
    cout<<"10b,";
    CardsRolled[i]=xRan;
    break;
case 44:
    cout<<"10c,";
    CardsRolled[i]=xRan;
    break;
case 45:
    cout<<"10d,";
    CardsRolled[i]=xRan;
    break;
case 46:
    cout<<"Ja,";
    CardsRolled[i]=xRan;
    break;
case 47:
    cout<<"Jb,";
    CardsRolled[i]=xRan;
    break;
case 48:
    cout<<"Jc,";
    CardsRolled[i]=xRan;
    break;
case 49:
    cout<<"Jd,";
    CardsRolled[i]=xRan;
    break;
case 50:
    cout<<"Qa,";
    CardsRolled[i]=xRan;
    break;
case 51:
    cout<<"Qb,";
    CardsRolled[i]=xRan;
    break;
case 52:
    cout<<"Qc,";
    CardsRolled[i]=xRan;
    break;
case 53:
    cout<<"Qd,";
    CardsRolled[i]=xRan;
    break;
case 54:
    cout<<"Joker,";
    CardsRolled[i]=xRan;
    break;


	}
    }

        sum+=CardsRolled[i];


        }
numb++;

    }

    }

using this code it just runs forever
Last edited on
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