Converting bases

[agirideep]

Hello, I am currently unsure on how to convert a binary base to a quantenary base.
Here is a function I have written for decimal to binary conversions but any hints or advice would be helpful, please don't give me the answer.

    for(int i = (sizeof(int) * 8) - 1; i >= 0; i--)
    {
       unsigned int o = (number >> i) & 01;
       os << o;
    }

[jonnin]

they all work the same way. Your issue is trying to see cute ways to implement, which is important for performance if you have a lot to do, but what is the PROCESS?

in binary... until zero...
take the remainder of 2 and divide by 2.
in base 10, take the remainder of 10 and divide by 10
etc. All the same, but you can optimize the code for each one.

[mbozzi]

Yours is a conversion from any positive number, not any decimal number, to base 2. The point is that there are no "decimal" numbers. Decimal, binary, quaternary, etc. are just properties of a number's representation.

#include <iostream>
#include <string>

// assumes nonnegative n, positive b, b <= strlen(digits)
std::string to_base(int n, int b, char const* digits = "0123456789abcdef") 
{ return (n/b? to_base(n/b, b, digits): "") + std::string(1, digits[n%b]); } 

int main()
{
  std::cout << to_base(17, 4) << '\n'; // convert 17 to base 4, output 101
}