Problem #36

#include <iostream>
#include <string>
#include <ctime>
#include <cmath>
#include <limits>

using namespace std;

bool isDecPal (int);
bool isBinPal (int);
string reverseString (string);
string cvt_binary(unsigned int);

int main() 
{
    clock_t start = clock();
    int total = 0;

    for (unsigned int i = 0; i < 1000000; i++)
        if (isDecPal (i))
            if (isBinPal (i))
                total += i;

    cout << total << endl 
         << "Process took " << (static_cast<double> (clock()) - start) / CLOCKS_PER_SEC << " seconds." << endl;
    system("pause");
    return 0;
}

bool isDecPal (int num)
{
    char buffer[32];
    string str;

    sprintf (buffer, "%i", num);
    str = buffer;

    if (str == reverseString (str))
        return true;
    return false;
}

bool isBinPal (int num)
{
    string str;

    str = cvt_binary (num);

    if (str == reverseString (str))
        return true;
    return false;
}


string reverseString (string str)
{
    string str2;

    for (unsigned int i = 0; i < str.size(); i++)
        str2 += str[str.size () - i - 1];
    return str2;
}

string cvt_binary(unsigned int input) 
{
    string result;

    if(input == 0) 
        return "0";

    for(int i = numeric_limits<unsigned int>::digits - 1; i >= 0; i--) 
        if(input & (1 << i)) 
            result += "1";
        else 
            if(!result.empty()) 
                result += "0";
    return result;
}