How to extract digits from a number in C? Begining from the most significant digit?

Question

Getting digits from a number beginning from the least significant in C is pretty easy:

#include 

int main()
{
    int num = 1024;

    while(         


        

Answer 1

Here is my try. Works for positive numbers only. Max range 2^64 (unsigned long long)

#include 
#include 

using namespace std;
using bignum = unsigned long long;

inline
bignum Power(unsigned x, unsigned y) {
    return y>0 ? x*Power(x,y-1) : 1;
}

// return digits count in a number
inline
int Numlen(bignum num) {
    return num<10 ? 1 : floor(log10(num))+1;
}

// get the starting divisor for our calculation
inline
bignum Getdivisor(unsigned factor) {
    return Power(10, factor);
}


int main()
{
    bignum num{3252198};
    //cin >> num;

    unsigned numdigits = Numlen(num);    
    auto divisor = Getdivisor(numdigits-1);

    while(num > 0) {

        cout << "digit = " << (num/divisor) << "\n";

        num %= divisor;
        divisor /= 10;
    }
}

/*
output:
digit = 3
digit = 2
digit = 5
digit = 2
digit = 1
digit = 9
digit = 8
*/