proc toroman(word n; *char buf) *char:
    *char parts = "M\e\eCM\eD\e\eCD\eC\e\eXC\eL\e\eXL\eX\e\eIX\eV\e\eIV\eI";
    [13]word sizes = (1000,900,500,400,100,90,50,40,10,9,5,4,1);
    channel output text roman;
    word part;

    open(roman, buf);
    while n > 0 do
        part := 0;
        while sizes[part]>n do part := part+1 od;
        write(roman; parts + 3*part);
        n := n - sizes[part]
    od;
    close(roman);
    buf
corp

proc test(word n) void:
    [32]char buf;
    writeln(n, ": ", toroman(n, &buf[0]))
corp

proc main() void:
    test(1666);
    test(2008);
    test(1001);
    test(1999);
    test(3888);
    test(2025)
corp