Rock Paper Scissors keeps messing up

Hello all,

This is my first time posting here but this project is due tonight and I've been stuck on this problem for the past 2 hours. I am new to C.

The assignment is based on one from 2 weeks ago, and basically we just have to simplify the code more instead of using if else's constantly we need to use a switch statement and typedef enum. It is okay to use the if elses in the cases to finish the little game.

When I run the program it takes 2 inputs for player 1 and player 2. I then run playGame which turns player 1's input into a choice. it uses that choice to run a switch statement and complete's it with the if elses inside, but unfortunately whenever I run it I keep getting "It's a draw!" regardless of what I input. I don't understand why it keeps only going to "It's a draw!" If anyone has some insight it would be greatly appreciated

Code:

---

#include <stdio.h>

typedef enum { ROCK = 1, PAPER, SCISSORS } Choice;
Choice choice;
char play1;
char play2;


void playGame(char play1, char play2);


int main(void)
{
        printf("Player 1 please choose <r>ock, <p>aper, or <s>cissors:");
        scanf("%c", &play1);
        getchar();
        printf("Player 2 please choose <r>ock, <p>aper, or <s>cissors:");
        scanf("%c", &play2);


        playGame(play1, play2);
        return 0;
}


void playGame(char play1, char play2)
{
        if (play1 == 'r' || 'R')
        {
                choice = ROCK;
        }
        else if (play1 == 'p' || 'P')
        {
                choice = PAPER;
        }
        else if (play1 == 's' || 'S')
        {
                choice = SCISSORS;
        }




        switch (choice)
        {
        case ROCK:
                if (play2 == 'r' || 'R')
                {
                        printf("It's a draw!\n");
                }
                else if (play2 == 'p' || 'P')
                {
                        printf("Player 2 wins! Paper covers Rock!\n");
                }
                else if (play2 == 's' || 'S')
                {
                        printf("Player 1 wins! Rock breaks Scissors!\n");
                }
                break;
        case PAPER:
                if (play2 == 'r' || 'R')
                {
                        printf("Player 1 wins! Paper covers Rock!\n");
                }
                else if (play2 == 'p' || 'P')
                {
                        printf("It's a draw!\n");
                }
                else if (play2 == 's' || 'S')
                {
                        printf("Player 2 wins! Scissors cut Paper!\n");
                }
                break;
        case SCISSORS:
                if (play2 == 'r' || 'R')
                {
                        printf("Player 2 wins! Rock breaks Scissors!\n");
                }
                else if (play2 == 'p' || 'P')
                {
                        printf("Player 1 wins! Scissors cut Paper!\n");
                }
                else if (play2 == 's' || 'S')
                {
                        printf("It's a draw!\n");
                }
                break;
        default:
                {
                break;
                }
        }
}

---

This is probably wrong:

Code:

---

if (play1 == 'r' || 'R')
{
    choice = ROCK;
}

---

What it means is "if the value of play1 is equal to 'r', or if the value of 'R' is non-zero, then assign the value of ROCK to choice". Since the value of 'R' is non-zero, the above code is equivalent to:

Code:

---

if (1)
{
    choice = ROCK;
}

---

which is equivalent to:

Code:

---

choice = ROCK;

---

which means that you wasted all your effort writing the if statement. What you probably wanted is "if the value of play1 is equal to 'r', or if the value of play1 is equal to 'R', then assign the value of ROCK to choice", i.e.,

Code:

---

if (play1 == 'r' || play1 == 'R')
{
    choice = ROCK;
}

---

Thank you so much! I'm not running on much sleep, so I never would have seen that. Also explains the spelling errors everywhere when I tried to explain the program. It runs perfectly now, thanks!

Instead of comparing the input to both upper and lower case, convert the input to one of them.

You could use a string to keep track of what beats what. It might be a slight overkill (or not) for rock-paper-scissors, but it works well when extended to the full rock-paper-scissors-lizard-spock.

Assuming opponent is already set to R, S, or P (or L or K) :

Code:

---

// rock-paper-scissors
char a[] = "RsSpPr";  // R beats s, S beats p, P beats r
int c = toupper(getchar());
char *p = strchr(a, c); // find uppercase match
if (!p) ; // error

if (opponent == c)
    ;  // tie
else if (opponent == toupper(p[1]))
    ;  // you win
else
    ;  // you lose



// rock-paper-scissors-lizard-spock (K is spock)
char a[] = "KsrSplPrkRlsLpk"
int c = toupper(getchar());
char *p = strchr(a, c);
if (!p) ; // error

if (opponent == c)
    ;  // tie
else if (opponent == toupper(p[1]) || opponent == toupper(p[2]))
    ;  // you win
else
    ;  // you lose

---

> If anyone has some insight it would be greatly appreciated
Well working on a problem (and asking questions) sooner than "this project is due tonight" would be a start. Consider this an effective lesson on how not to do time management.

How To Ask Questions The Smart Way

I had started it the day before and emailed my professor about my problem, but unfortunately he doesn't respond very quickly. The next day I had been trying to work on it but I couldn't figure it out, hence why I came here.

While time management has not always been my strong suit, in this case it was not an issue (We only have 2 days to do our projects since it's a sped up summer course anyways). I will keep your advice in mind though, thanks!