Help Please!! input not triggering the correct if statement

[imprudentspace]

I am writing a program that converts binary to decimal and vice versa. When the user enters a character choice (D, B, or Q to quit) that actions is performed. When I enter a 'B' to go from Binary to Decimal, it acts as if I entered 'D' to go from Decimal to Binary. This seems like a small mistake but I just don't know why when I enter 'B' it acts as if I input 'D'. The code is found in the main() function.

#include "stdafx.h"
#include <iostream>
#include <limits>
#include <math.h>

using namespace System;
using namespace std;

void ConvertByRecursion(long long n);
long long getDecimal();
long long getBinary();
long long BinaryToDecimal(long long);

int main()
{
    long long n, result;
	char choice;
	cout << "Decimal-Binary Conversions By Fedaa Musleh" << endl;
	cout << "Welcome to the Decimal to Binary Converter!" << endl;
	while (choice != 'Q' || 'q')
	{
		cout << "Dec2Bin or Bin2Dec or Quit? (D/B/Q): ";
		cin >> choice;
		if (choice == 'D' || 'd')
		{
			n = getDecimal();
			while (n !=0)
			{
				ConvertByRecursion(n);
				cout << endl << endl;
				n = getDecimal();
			}
		}
		else if (choice == 'B' || 'b')
		{
			n = getBinary();
			result = BinaryToDecimal(n);
			cout << "\nTherefore the binary value is: " << result << endl;
			cout << "\nThanks for using the decimal converter!" << endl;
		}
	}
	cout << "\nThanks for using the Decimal-Binary converter!" << endl;

	system("Pause");
    return 0;
}

long long getDecimal()
{
	long long n;
	bool baddata = false;
	
	do
	{
		baddata = false;
		cout << "Please enter your decimal value to convert (0 to quit): ";
		cin >> n;

		if(!cin.good())
		{
			cin.clear();
			cin.ignore(numeric_limits<streamsize>::max(), '\n');
			cout << "I could not decipher your input as a decimal value." << endl;
			baddata = true;
		}
		else if (n < 0)
		{
			cout << "Please enter a non-negative value." << endl;
			baddata = true;
		}
	} while (baddata);

	return n;
}

void ConvertByRecursion(long long n)
{
	long long r;
	long long newval;

	r = n % 2;
	newval = n / 2;
	Console::WriteLine("Decimal {0,12:D} divided by 2 = {1, 12:D} w/Remainder of: {2,3:D} ", n, newval, r);
	if (newval > 0)
	{
		ConvertByRecursion(newval);
	}
	else
	{
		cout << "\nTherefore, by recursion, the binary value of " << n << " is: ";
	}
	cout << r;
}

long long getBinary()
{
	long long n;
	bool baddata = false;
	do
	{
		baddata = false;
		cout << "Please enter your Binary value to convert to Decimal: (0 to Quit). ";
		cin >> n;
		if (!cin.good())
		{
			cin.clear();
			cin.ignore(numeric_limits<streamsize>::max(), '\n');
			cout << "I could not decipher your input as a decimal value " << endl;
			baddata = true;
		}
		else if (n < 0)
		{
			cout << "Please enter a non-negative value." << endl;
			baddata = true;
		}
	} while (baddata);
	
	return n;
}

long long BinaryToDecimal(long long n)
{
	long long value = 0, i = 0, binarydigit, position;
	while (n != 0)
	{
		binarydigit = n % 10;
		position = pow(2,i);
		value = value + binarydigit*position;
		n = n/10;
		i++;
	}
	return value;
}

[imprudentspace]

Bump. Can anyone help me out here? It's a small error but it's driving me crazy and I don't have much time until this is due.

[jlb]

while (choice != 'Q' || 'q')
This is not how you combine comparisons in C++, you need a comparison for both sides of your comparison operator:
By the way your choice of comparison operator is incorrect you should be using the && operator instead.
while (choice != 'Q' && choice != 'q')

I try to avoid "negative" logic in my control statements and in this instance it would probably be better to just use the toupper or tolower functions to force the input into a "known" case.

while(toupper(choice) != 'Q')

[imprudentspace]

I've followed your directions, however when I input 'b' or 'd' it does not trigger the correct if statement. When 'q' is pressed, the program quits as intended. When I use the || operator the program works as intended.

[jonnin]

lets see the updated code, just the segment of interest not all of it.
you should initialize choice. It could start as q at random as you have it.

[imprudentspace]

cout << "Dec2Bin or Bin2Dec or Quit? (D/B/Q): ";
		cin >> choice;
		if (choice == 'D' || choice == 'd')
		{
			n = getDecimal();
			while (n !=0)
			{
				ConvertByRecursion(n);
				cout << endl << endl;
				n = getDecimal();
			}
		}
		else if (choice == 'B' || choice == 'b')
		{
			n = getBinary();
			result = BinaryToDecimal(n);
			cout << "\nTherefore the binary value is: " << result << endl;
			cout << "\nThanks for using the decimal converter!" << endl;
		}

Now that I've solved the input problem, I need help with the binary to decimal conversion. I am supposed to use the recursive method there, and I should have data validation so that only 1's and 0's are accepted as input. Can you assist me there?