Conversión entre bases numéricas

binaryToDecimal.cpp

#include <iostream>
#include <math.h>

using namespace std;

/*
 * CONVERT BINARY '11011' TO DECIMAL
 * |__c__|__r__|__i__|_2^i_|_dec_|
 * | 1101|  1  |  0  |__1__|__1__|
 * |  110|  1  |  1  |__2__|__2__|
 * |   10|  0  |  2  |__4__|__0__|
 * |    1|  1  |  3  |__8__|__8__|
 * |    0|  1  |  4  |_16__|_16__|
 * |-----|-----|-----|-----|_27__|
*/

int b2d(int c, int r, int i)
{
    if (r < 0 && r > 1) return -1;
    int res = r * pow(2, i);

    if (c != 0)
    {
        int exp = b2d(c / 10, c % 10, ++i);
        return (exp >= 0) ? res + exp : exp;
    }
}

int b2d(int n)
{
    return b2d(n / 10, n % 10, 0);
}

int main(int argc, char const *argv[])
{
    int binario = 0;
    cout << "Binario a convertir: " << endl;
    cin >> binario;
    
    cout << "Binario:" << binario << endl;
    int decimal = b2d(binario);
    cout << "Decimal:" << decimal << endl;
    
    return 0;
}