Monty hall show simulation unexpected results - c

Question

#include <stdio.h>
#include <time.h>
int main (void)
{
int pickedDoor, remainingDoor, hostDoor, winningDoor, option, games = 0, wins = 0;
float frequency = 0;
srand (time(NULL));
while (1)
{
printf ("Pick one of the three doors infront of you, which do you want?\n");
scanf ("%d", &pickedDoor);
if (pickedDoor > 3 || pickedDoor <= 0)
{
break;
}
winningDoor = rand() % 3 + 1;
do
{
hostDoor = rand() % 3 + 1;
} while (hostDoor == pickedDoor || hostDoor == winningDoor);
do
{
remainingDoor = rand() % 3+1;
} while (remainingDoor == pickedDoor || remainingDoor == hostDoor);
printf ("The door the host picked is %d\n", hostDoor);
do
{
printf("Do you want to switch doors? Please enter in the door you want:\n", hostdoor);
scanf("%d", &option);
if (option > 3 || option <= 0)
{return 0;}
}while (option == hostDoor);
if (option == winningDoor)
{
printf("You Won!\n");
wins++;
}
else
{
printf("YOU LOSE!\n");
}
games++;
}
frequency = ((float) wins / games) *100;
printf ("The number of games that you won is %d\n", wins);
printf ("The frequency of winning is %.0f%%\n", frequency);
return 0;
}
Hi, this is my version of the monty hall game show, im getting unexpected results though.
sometimes when I enter in a door for my option it just brings me back to the "pick one of the three doors infront of you" statement, when it should tell me if i have won or lost.
I think this is because the "option" door is equal to the "hostDoor.
I thought having "option != hostDoor" would fix it but it does not.
If i am correct in that assumption how can I fix it? If not why is it not working and how can I fix it?

Answer 1

To simulate correctly, OP needs to show the host door.
do {
printf("Do you want to switch doors? Please enter in the door you want:\n");
scanf("%d", &option);
if (option > 3 || option <= 0 ) {
return 0;
}
} while (option == hostDoor);
// instead of
#if 0
printf("Do you want to switch doors? Please enter in the door you want:\n");
scanf("%d", &option);
if (option > 3 || option <= 0 ) { return 0; }
#endif
To deal with OP " it should tell me if i have won or lost." problem, change
else if (option == remainingDoor)
to
else
Your scanf("%d", &option) is OK. I prefer the fgets()/sscanf() combo and its alway useful to check the result of scanf() family, but that is not your issue here.

Answer 2

Its because of these:
scanf ("%d", &pickedDoor);// reads \n after the last input
scanf("%d", &option); // reads \n after the last input
**option != hostDoor; // completely useless .. get rid of it**
I would suggest putting a getchar() after each scanf to get rid of the \n character
so something like this:
#include <stdio.h>
#include <time.h>
int main (void)
{
int pickedDoor, remainingDoor, hostDoor, winningDoor, option, games = 0, wins = 0;
char collect; //variable to collect any extra input like \n
float frequency = 0;
srand (time(NULL));
while (1)
{
printf ("Pick one of the three doors infront of you, which do you want?\n");
scanf ("%d", &pickedDoor);
collect = getchar(); // get rid of the \n from the input stream
printf("collect = %c\n",collect);
if(collect!='\n'){ // is it actually a \n or did you take in something else
putchar(collect); // if it isn't \n put it back
}
if (pickedDoor > 3 || pickedDoor <= 0)
{
break;
}
winningDoor = rand() % 3 + 1;
do
{
hostDoor = rand() % 3 + 1;
} while (hostDoor == pickedDoor || hostDoor == winningDoor);
do
{
remainingDoor = rand() % 3+1;
} while (remainingDoor == pickedDoor || remainingDoor == hostDoor);
printf("Do you want to switch doors? Please enter in the door you want:\n");
scanf("%d", &option);
collect = getchar(); // get rid of the \n from the input stream
printf("collect = %c\n",collect);
if(collect!='\n'){ // is it actually a \n or did you take in something else
putchar(collect); // if it isn't \n put it back
}
if (option > 3 || option <= 0 )
{
return 0;
}
if (option == winningDoor)
{
printf("You Won!\n");
wins++;
}
else if (option == remainingDoor)
{
printf("YOU LOSE!\n");
}
games++;
}
frequency = ((float) wins / games) *100;
printf ("The number of games that you won is %d\n", wins);
printf ("The frequency of winning is %.0f%%\n", frequency);
return 0;
}
Another more efficient way would be to use fgets or to have error checks on scanf() itself

Answer 3

srand and rand belongs to stdlib header file
#include<stdlib.h> // include this header file
option != hostDoor; // this statement does not do anything
and your else if (option == remainingDoor) should be else { printf("you lose");}