Decimal to binary

// Example program
#include <iostream>
#include <string>
#include <cmath>
using namespace std;

unsigned GetNumberOfDigits (unsigned i)
{
    return i > 0 ? (int) log10 ((double) i) + 1 : 1;
}

void reverseStr(string& str)
{
    int n = str.length();

    // Swap character starting from two
    // corners
    for (int i = 0; i < n / 2; i++)
        swap(str[i], str[n - i - 1]);
}


string decimalToBinary(int input, int len=0)
{
    len=1+floor(log10(input));//c++ code lib (cmath)
    int temp = input;
    string output = "";
    while(1)
    {
        if(temp==1)
        {
         output +="1";
         break;

        }
        int tempBin = temp % 2;
        char tempChar = tempBin+48;
        output += tempChar;
        temp = temp / 2;
        len = GetNumberOfDigits(temp);

    }
    reverseStr(output);
    return output;

}


int main()
{
  int n = 1001;
  string outputNumber = decimalToBinary(n);
  cout << "OUTPUT " << outputNumber << endl;

}