include "cowgol.coh";

# Calculate the digital root and additive persistance of a number
# in a given base
sub digital_root(n: uint32, base: uint32): (root: uint32, pers: uint8) is
    pers := 0;
    while base < n loop
        var step: uint32 := 0;
        while n > 0 loop
            step := step + (n % base);
            n := n / base;
        end loop;
        pers := pers + 1;
        n := step;
    end loop;
    root := n;
end sub;

# Print digital root and persistence (in base 10)
sub test(n: uint32) is
    var root: uint32;
    var pers: uint8;

    (root, pers) := digital_root(n, 10);

    print_i32(n);
    print(": root = ");
    print_i32(root);
    print(", persistence = ");
    print_i8(pers);
    print_nl();
end sub;

test(4);
test(627615);
test(39390);
test(588225);
test(9992);