Always goes to error

[Eraun]

I'm pretty new to c++ and I've been trying to create this rock paper scissors game where you can enter the word for what you chose and play against a computer. Although I am entering either rock, paper, or scissors exactly, it always goes to default in the last switch statement and says error. I have no idea what the problem is. Anybody here know what the error may be? I'm using online gbd to compile and execute the code.

#include <iostream>
#include <stdlib.h>
#include <ctime>
#include <string>

int main()
{

srand(time(NULL));

int rando = rand() % 3;
int pNumb;
std::string pTurn ("");
std::string cpTurn ("");
std::string p1 ("The computer chose ");
std::string p2 (" and you chose ");
std::string win (" so you win!\n");
std::string lose (" so you lost :(.\n");
std::string error ("error\n");
std::string tied (" so you tied!\n");
std::string r ("rock");
std::string p ("paper");
std::string s ("scissors");
int numbDiff = rando - pNumb;

switch (rando) {
    case 0: cpTurn = r;
            break;
    case 1: cpTurn = p;
            break;
    case 2: cpTurn = s;
            break;
    default: cpTurn = error;
            break;
}

std::cout << "Chose rock, paper, or scissors!(exactly as stated)\n";
std::cin >> pTurn;

if (pTurn == r) {
    pNumb = 0;
}
else if (pTurn == p) {
    pNumb = 1;
}
else if (pTurn == s) {
    pNumb = 2;
}

switch (numbDiff) {
    case -2: std::cout << p1 << cpTurn << p2 << pTurn << lose;
            break;
    case -1: std::cout << p1 << cpTurn << p2 << pTurn << win;
            break;
    case 0: std::cout << p1 << cpTurn << p2 << pTurn << tied;
            break;
    case 1: std::cout << p1 << cpTurn << p2 << pTurn << lose;
            break;
    case 2: std::cout << p1 << cpTurn << p2 << pTurn << win;
            break;
    default: std::cout << error;
            break;
}


}

[Ganado]

On line 24, what do you think the value of pNumb is?

Always compile with warnings enabled.

 In function 'int main()':
24:24: warning: 'pNumb' may be used uninitialized in this function [-Wmaybe-uninitialized]

[Cheddar99]

Also, in line 37 you ask the user to enter

Chose rock, paper, or scissors!(exactly as stated)

, but then check for r, p, or s.

Surely you want to ask something like:

std::cout << "Choose (r)ock, (p)aper, or (s)cissors! (r, p, or s)\n";
std::cin >> pTurn;

See posts below. I hadn't realized the strings for "rock", "paper" and "scissors" are defined at the top of the program.

[Ganado]

Oh, good catch. And also, note that on lines 40-48, you assign pNumb a new value, but then you never actually use pNumb again. If you want numbDiff to have an updated value, you need to assign to numbDiff after you assign to pNumb.

[dhayden]

Eraun, I'm curious, did you think that numbDiff = rando - pNumb would cause numbDiff to be updated when pNumb was updated? I've seen many beginners assign values to variables too early and I wonder if they think that C++ programs work like spreadsheet formulas, where the value automatically updates when a component of the formula updates.

but then check for r, p, or s.

. That's okay. r, p, and s are strings with the values "rock" "paper" and "scissors". See lines 21-23

[Cheddar99]

@dhayden - Oh yeah, yeah. Of course; didn't notice that up top, although it does seem a slightly roundabout way of doing it. I'll amend my post.

[Eraun]

Alright, so I put the numbDiff = rando - pNumb after the if then statement where pNumb is set. That fixed it. Thanks guys.