Re: [Dev-C++] die rolling problem

[PETER C. <pca...@cc...>]

per, i follow your logic up until:
"Maybe you somewhere in the program - in your first fir loop, where you
>throw your dices - should use the first array and do:
>  faces[face-1]++;
>to count up number on ones, twoes... while you are busy rolling the
>dices."

how would i implement the array into counting how many ties a number comes up while at the same time not incrementing the number of rolls? i understand that faces[0]=faces[1-1], for example but i don't know how to use it properly. i tried the do..while loop below but i know taht i am not using it properly.
thanx peter

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
int main()
{
    int faces[6] = {0};
	int face_1, face_2, face_3, face_4, face_5, face_6;
	face_1 = faces[0];
	face_2 = faces[1];
	face_3 = faces[2];
	face_4 = faces[3];
	face_5 = faces[4];
	face_6 = faces[5];

    int rolls;
    cout << "how many times do you want to roll the die? ";     //how many times to roll die
    cin >> rolls; 

	srand(time(0));
	int face;
	for(int i= 0; i < rolls; i++){
		do{
            face= rand();
	    face= 1+ face%6;
	    cout << "the die has rolled a:" << face << endl;
		}while (faces[face-1]++);


	}



return 0;

}


---------- Original Message ----------------------------------
From: Per Westermark <pw...@ia...>
Date: 	Tue, 6 Jul 2004 20:11:23 +0200 (CEST)

>
>
>Let's see now:
>
>You have one array
>  int faces[6]
>which you don't seem to use anywhere in your program - other than to
>assign uninitialized variables (face_1) to index position 0:
>  int face_1;
>  faces[0] = face_1;
>Maybe you wanted to write:
>  face_1 = faces[0];
>since the goal should be that faces[0] stored the count of ones you got
>from all the rolls?
>
>Then you have one other array
>  int die[6] = {1,2,3,4,5,6};
>that is most definitely not needed.
>
>Maybe you somewhere in the program - in your first fir loop, where you
>throw your dices - should use the first array and do:
>  faces[face-1]++;
>to count up number on ones, twoes... while you are busy rolling the
>dices.
>
>Aftwerards, faces[0] would be number of times you got a one. faces[1]
>would be the number of times you got a two etc and faces[0] + faces[1] +
>... + faces[5] would be the total number of times you rolled the dice,
>i.e. the same as the value rolls. 100*faces[0] / rolls would then be
>number of times you got a one.
>
>Since faces[0] .. faces[5] would then contain counted values, you never
>need a second for loop in the program for building statistics. You could
>however use the second loop to emit your 6 percentages: probability of
>getting a one, probability of getting a two...
>
>I think I recommended you once before to always build your programs with
>the setting -Wall active. That would have generated a warning about face_1
>being used without having been initialized. Always let the compiler
>generate as much warnings as possible. For a biginning programmer, all
>warnings are useful. If you think a warning is stupid, you should know
>specifically why the compiler emitted the warning, and why the warning
>isn't apropriate for your specific program. When you are ready to keep a 5
>minute presentation in front of your class about a specific warning, then
>you have enough knowledge to decide when to ignore warnings of that
>specific type. Before that, you should treat warnings as errors, and make
>sure your code compiles with zero warnings at the highest warning level
>(-Wall).
>
>/Per W
>
>On Tue, 6 Jul 2004, PETER CAMPOS wrote:
>
>> Remarks by per are below..i attempted to set up a counter to count the number of times a die comes up and from that calculate the percentage. so far i get very small negative numbers...
>> am i going in the correct direction?
>> panos/peter
>>
>> #include <iostream>
>> #include <ctime>
>> #include <cstdlib>
>> using namespace std;
>> int main()
>> {
>>
>>     int rolls;
>>     cout << "how many times do you want to roll the die? ";     //how many times to roll die
>>     cin >> rolls;                                               //user input
>>     int faces[6] = {0};                                         //array for storage of faces of die.
>>                                                                 //used later to calculate percentage
>>     int face;
>>     srand(time(0));                                             //user wants new random #'s generated each time
>>     int face_per;
>>
>>     int die[6] = {1,2,3,4,5,6};
>>         for(int i = 0; i < rolls; i++){
>>             face = rand();
>>             face = 1+ face%6;
>>         cout << "the die has rolled: " << face << endl;
>>     }
>>
>>     int face_1;
>>     int face_1_occur;
>>     faces[0] = face_1;
>>     face_1_occur = 0;
>>     for(int i =0; i<rolls; i++){
>>         face_1_occur = face_1 + 1;                               //counter for face 1
>>
>>     double prob_1 = face_1_occur * 100/rolls;
>>     cout << "the probability to roll a 1 is" << prob_1 << endl;
>> }
>>      return 0;
>>     }
>>
>> 1) You don't store an infinite number of dice values - no need to. Just
>> emit the value for each throw on the fly. Then keep 6 counters - one for
>> each of the 6 faces of the dice.
>>
>> 2) Emit the 6 counters. Percentage is just # of occurences * 100 / total
>> throws.
>>
>> 3) If the values you put into an array are in range 1-6, of course the
>> values stay in that range. However, normally when counting number of
>> times you get a one, a two etc, you store that in an array with index 0 to
>> 5, since all arrays in C and C++ starts with index zero.
>>
>> /Per W
>
>
 

 
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