Thread View: sci.math.stat
2 messages
2 total messages
Started by Peter Pui Tak Chiu
Sun, 13 Sep 1992 18:53
FULL HOUSE (REVISED)
Author: Peter Pui Tak Chiu
Date: Sun, 13 Sep 1992 18:53
Date: Sun, 13 Sep 1992 18:53
56 lines
1549 bytes
1549 bytes
// this previous version of this program assumes that we are drawing from
// an infinite deck. (which is a bug).
// now this version has no such problem...
// but still the probability is around 0.004...
// which is four times the theoretical value 0.001441
// what's wrong???!!!
#include <iostream.h>
#include <time.h>
#include <stdlib.h>
#include <math.h>
static int hand[5];
long COUNTER=0, GOOD=0;
int getRandom(){
int n,BAD=1;
while(BAD){
n=rand()%52+1;
for(int i=0;i<5;i++){
int FLAG=0;
if(n==hand[i])FLAG=1;
if(!FLAG)BAD=0;
}}
return(n);
}
void init(){
for(int i=0;i<5;i++)hand[i]=0;
for(i=0;i<5;i++)hand[i]=getRandom();
for(i=0;i<5;i++)hand[i]=hand[i]%13;
}
int fullhouse(){
int counter[13],flag2=0,flag3=0;
for(int i=0;i<13;i++)counter[i]=0;
for(i=0;i<5;i++)counter[hand[i]]++;
for(i=0;i<13;i++){
if(counter[i]==2)flag2++;
if(counter[i]==3)flag3++;
}
return(flag2&&flag3);
}
main(){
randomize();
while(1){
COUNTER++;
init();
if(fullhouse())GOOD++;
if(!fmod(COUNTER,10000))cerr<<COUNTER<<double(GOOD)/COUNTER<<"\n";
}}
Re: FULL HOUSE (REVISED)
Author: Arthur Rubin
Date: Tue, 15 Sep 1992 21:27
Date: Tue, 15 Sep 1992 21:27
25 lines
1527 bytes
1527 bytes
In <1992Sep13.185343.26823@wuecl.wustl.edu> ppc1@cec1.wustl.edu (Peter Pui Tak Chiu) writes: >// this previous version of this program assumes that we are drawing from >// an infinite deck. (which is a bug). >// now this version has no such problem... >// but still the probability is around 0.004... >// which is four times the theoretical value 0.001441 The program looks more or less correct, although I only know C rather than C++ so I can't verify the output line, but... The low order bits of random numbers are freqently systematic. If, for instance, the low 2 bits of rand move systematically among the suits with period 4, and, assuming the remaining bits are sufficiently random (possibly true), we would have the probablity of a full house (2/13)^3 = .00364 -- Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea 216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal) My opinions are my own, and do not represent those of my employer. My interaction with our news system is unstable; please mail anything important.
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