Error In a While Loop

I am doing some Programming exercises from the book I am learning C++ from, C++ Primer Plus. I was doing one of the examples and I have ran into a problem with some of my code.

Code:

#include <iostream>


using namespace std;


int main()
{
    cout << "Please enter one of the following choices: \n";
    cout << "c) carnivore    p)pianist\nt)tree          g)game\n";
    char in;
    cin >> in;
    while( in != 'c' || 'p' || 't' || 'g'){
        cout<<"Please enter a c, p, t, or g: ";
        cin >> in;
    }
    cout<< endl;
    switch(in){
        case 'c':
            cout<<"A lion is a carnivore.";
            break;
        case 'p':
            cout<<"A pianist is a piano player";
            break;
        case 't':
            cout<<"A maple is a tree.";
            break;
        case 'g':
            cout<<"Mine sweeper is a game.";
            break;
    }
    return 0;
}

I believe everything is working as I want except for the while loop

Code:

while( in != 'c' || 'p' || 't' || 'g'){
        cout<<"Please enter a c, p, t, or g: ";
        cin >> in;
    }

I have tried putting the stuff on the right side of the != in parenthesis, changing it to a == and putting a ! infront of the entire thing.

Does anyone have any suggestions on what might be wrong with my code? I am not able to see what all is wrong.

This is what you mean:

Code:

while( in != 'c' && in != 'p' && in != 't' && in != 'g')

You must have both sides of the equation for each AND or OR.

Code:

while( a == b || b == c)

Jim

Oh wow I feel like I should of known that. Thank you to both of you for the help.