Takes an integer between 1 and 3999 and converts it to Roman Numerals
Tcl, 32 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | proc toRoman {arabic} {
#September 2001 by George M Jempty: jb4mt@webfielding.com
if {![string is integer -strict $arabic] || $arabic < 1 || $arabic > 3999} {
return -code error "Please retry with an integer from 1 to 3999"
}
set numerals [list I V X L C D M]
set index 0
set roman ""
while {$arabic} {
set digit [expr {$arabic%10}]
set arabic [expr {$arabic/10}]
set place ""
if {$digit == 4 || $digit == 9} {
set place [lindex $numerals [expr {$digit/4 + $index}]]
set place [lindex $numerals $index]$place
} else {
for {set pad 0} {$pad < [expr {$digit%5}]} {incr pad} {
set place [lindex $numerals $index]$place
}
if {$digit >= 5} {
set place [lindex $numerals [expr {$index+1}]]$place
}
}
incr index 2
set roman $place$roman
}
return $roman
}
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Limited to numbers under 4000 because the appropriate character for 5000 (and therefore one thousand fewer than 5000, ergo 4000) is not an ASCII character.
Needs work. This unfortunately spins indefinitely when I do 'toRoman 99'. Also, expressions should be braced for speed.
One fix down one to go. OK, I fixed the endless loop thing, caused by me incompletely eradicating an unrequired variable and then not testing it.
When you say grouping "expressions" with braces, do you mean my math "expr"s?
Richard Suchenwirth has a nice slick way of doing arabic->roman conversion (see http://mini.net/tcl/1749 for more details):