Logical Operators in C causing issue with my loop? - c

Question

I am making a game for an assignment where there are 2 players and each turn the player rolls 2 die. When I ask the player if they want to roll again everything goes south from there. I'm confused because even if I change my rollAgain character to 'n' it still plays my loop where I want it to run only if rollAgain is 'y' or 'Y'. This is my first program in C, I have only programmed in Java previously. I feel like I must be checking the logical operators incorrectly in my while loop but idk what I'm doing wrong, I've looked over all the code several times now.
Here is my code:
#include <stdio.h>
#include <stdlib.h> // NULL constant, srand() & rand() functions
#include <time.h> // access your computer’s clock time
// function prototype statements
int rollDice();
int calcPoints(int die1, int die2);
char checkOne(int die1, int die2);
int main()
{
int p1Score = 0;
int p2Score = 0;
int turnTotal = 0;
char rollAgain = 'Y';
char rolled1 = 'N';
int die1;
int die2;
printf("Welcome to the Pig Game. Each turn the player rolls two dice repeatedly until a single 1 is rolled or the player holds.\n\n");
printf("If a single 1 is rolled all points are lost. If the player holds, all earned points are kept.\n");
printf("If double 1's are rolled 25 points are earned, if any other doubles are rolled the value is doubled.\n");
printf("Player 1 has an advantage because they get to go first, the youngest player gets to be Player 1.\n\n");
printf("First player to 100 points wins, let the games begin!!!\n\n");
do
{
//----------------------P1's turn starts----------------------------------------
while ((rollAgain == 'Y' || rollAgain == 'y') && rolled1 == 'N')
{
die1 = rollDice(); //roll die 1
die2 = rollDice(); //roll die 2
printf("Player 1 rolls %d, and %d\n", die1, die2);
rolled1 = checkOne(die1, die2); //check if turn ending 1 is rolled if they did the below while loop will not run and the current while loop will end.
if(rolled1 == 'N') //if a single 1 wasn't rolled calculate total for the turn
{
turnTotal += calcPoints(die1, die2);
printf("Player 1 your turn total so far is %d. Would you like to roll again?\n", turnTotal);
fflush(stdin);
scanf_s("%c", &rollAgain);
}
}
//-------------------------P1's turn is now over---------------------------------
if (rolled1 == 'Y') //turnTotal isn't added to p1Score
{
printf("Sorry Player 1 your turn is over because you rolled a 1 on a single die :(\n");
printf("Your total score is now: %d.\n", p1Score);
}
else //player1 must have held
{
printf("Congratulations on scoring %d point this turn Player 1!\n", turnTotal);
p1Score += turnTotal;
printf("Your total score is now: %d.\n", p1Score);
}
//reset variables to start p2s turn
turnTotal = 0;
rolled1 = 'N';
rollAgain = 'Y';
//----------------------P2's turn starts----------------------------------------
while ((rollAgain == 'Y' || rollAgain == 'y') && rolled1 == 'N' && p1Score < 100) //player2's turn should not start if player 1 has already won the game so we must check p1's score as well
{
int die1 = rollDice(); //roll die 1
int die2 = rollDice(); //roll die 2
printf("Player 2 rolls %d, and %d\n", die1, die2);
rolled1 = checkOne(die1, die2); //check if turn ending 1 is rolled if it was the below while loop will not run and the current while loop will end.
if(rolled1 == 'N') //if a single 1 wasn't rolled calculate total for the turn
{
turnTotal += calcPoints(die1, die2);
printf("Player 2 your turn total so far is %d. Would you like to roll again?\n", turnTotal);
fflush(stdin);
scanf_s("%c", &rollAgain);
}
}
//-------------------------P2's turn is now over---------------------------------
if (rolled1 == 'Y' && p1Score < 100) //turnTotal isn't added to p1Score
{
printf("Sorry Player 2 your turn is over because you rolled a 1 on a single die :(\n");
printf("Your total score is now: %d.\n", p2Score);
}
if (rolled1 == 'N' && p1Score < 100) //player2 must have held, use an if statement rather than else because we don't want this code to play if p1 has already won
{
printf("Congratulations on scoring %d point this turn Player 2!\n", turnTotal);
p2Score += turnTotal;
printf("Your total score is now: %d.\n", p2Score);
}
//reset variables for p1's turn
turnTotal = 0;
rolled1 = 'N';
rollAgain = 'Y';
//if either player's score is > 100 the game is now over so the game ending code will now play
} while (p1Score < 100 && p2Score < 100);
if (p1Score >= 100) //player 1 has won, congratulate them
printf("Congratulations Player 1, you have won the game! Pat yourself on the back!\n");
else //player 1 didn't win so player 2 must have won since there are no draws
printf("Congratulations Player 2, you have won the game! You are awesome!\n");
return 0; //end main
}
//function rollDice rolles the dice for the player using a random number between 1-6.
int rollDice()
{
// seed the random number generator using the computers clock
srand(time(0));
//generate a random number between 1-6
int num = (rand() % 6) + 1;
return num;
}
//function calcPoints that calculates how many points the player earned.
int calcPoints(int die1, int die2)
{
int points;
if (die1 == die2) //check if doubles were rolled
{
//snake eyes = 25 points
if (die1 == 1)
points = 25;
//regular doubles = the value on the dice *2
else
points = (die1 + die2) * 2;
}
else //doubled weren't rolled
points = die1 + die2;
return points;
}
//function checkOne that checks if the player rolled a single 1 during their turn.
char checkOne(int die1, int die2)
{
if (die1 == 1 && die2 != 1)
return 'Y';
else if (die1 != 1 && die2 == 1)
return 'Y';
else
return 'N';
}
The players turn is supposed to end if a single 1 is rolled.
I would really appreciate any help I'm not sure where I am going wrong. The code just has a mind of its own after it asks if I want to roll again.
Player 1 rolls 2, and 2
Player 1 your turn total so far is 8. Would you like to roll again?
y
Player 1 rolls 3, and 3
Player 1 your turn total so far is 20. Would you like to roll again?
Congratulations on scoring 20 point this turn Player 1!
Your total score is now: 20.
Player 2 rolls 3, and 3
Player 2 your turn total so far is 12. Would you like to roll again?
this is the output I get if I say yes to rolling again. At the end of this output it allows me to input if I want to roll again.
Player 1 rolls 3, and 3
Player 1 your turn total so far is 12. Would you like to roll again?
n
Congratulations on scoring 12 point this turn Player 1!
Your total score is now: 12.
Player 2 rolls 1, and 1
Player 2 your turn total so far is 25. Would you like to roll again?
Congratulations on scoring 25 point this turn Player 2!
Your total score is now: 25.
Player 1 rolls 1, and 1
Player 1 your turn total so far is 25. Would you like to roll again?
this is the output I get if I say no to rolling again. At the end of this output it allows me to input if I want to roll again.

Answer 1

There are multiple classic issues in your code:
fflush(stdin); has undefined behavior. Just remove this statement, it does not consume the pending input in stdin.
scanf_s("%c", &rollAgain); will read the pending newline in the input stream. To skip it, you can just add a space in the format string and you must test if scanf_s succeeded to avoid undefined behavior at end of file:
if (scanf_s(" %c", &rollAgain) != 1) {
exit(1); // unexpected end of file or some other error
}
You should not reinitialize the random number generator every time you roll a die, just once at the beginning of the program (move the srand() function call to the beginning of the main function, and pass it clock() that varies much more rapidly than time(NULL)):
//function rollDice rolls the die for the player using a random number between 1-6.
int rollDice() {
//generate a random number between 1-6
return (rand() % 6) + 1;
}