Question

I am new to C++ development and I was hoping someone could help me with something I have been trying to do.

Say for example I want a function that will, given an integer input, return the number of distinct digits it contains.

So for example, if I have three integers:

int a = 19876;
int b = 25644;
int c = 4444;

If I pass ‘a’ into the function, I would expect the number 5 to be returned.
If ‘b’ was passed into the function, I would expect ‘4’ to be returned,
If ‘c’ was passed into the function, then 1 would be returned, as they are the number of distinct numbers.

Could someone please illustrate how I could achieve this?

Answer 1

You mean you want to find the number of different decimal digit in the integer?

int distinct_digits(int value) {
    std::ostringstream out;
    out << value;
    std::string digits = out.str();
    std::sort(digits.begin(), digits.end());
    return std::unique(digits.begin(), digits.end()) - digits.begin();
}

(not compiled or tested but the basic idea should work)