I've written three versions of a function which returns the lower case of an upper case alpha char passed to it. If it is passed a char which is not an upper case alpha it returns the input unmodified. All three versions have been tested.
Which version do you prefer? Why?
function locase(ch : char) : char ;
{
case version - jumps to the correct answer and returns
}
begin
case ch of
'A' : locase := 'a' ;
'B' : locase := 'b' ;
'C' : locase := 'c' ;
'D' : locase := 'd' ;
'E' : locase := 'e' ;
'F' : locase := 'f' ;
'G' : locase := 'g' ;
'H' : locase := 'h' ;
'I' : locase := 'i' ;
'J' : locase := 'j' ;
'K' : locase := 'k' ;
'L' : locase := 'l' ;
'M' : locase := 'm' ;
'N' : locase := 'n' ;
'O' : locase := 'o' ;
'P' : locase := 'p' ;
'Q' : locase := 'q' ;
'R' : locase := 'r' ;
'S' : locase := 's' ;
'T' : locase := 't' ;
'U' : locase := 'u' ;
'V' : locase := 'v' ;
'W' : locase := 'w' ;
'X' : locase := 'x' ;
'Y' : locase := 'y' ;
'Z' : locase := 'z'
else
locase := ch
end { case }
end ;
function locase(ch : char) : char ;
{
offset version - computes the offset and shifts the char
}
CONST
OFFSET = ord('a') - ord('A') ;
UPPERS = ['A' .. 'Z'] ;
begin
if ch in UPPERS then
locase := chr(ord(ch) + OFFSET)
else
locase := ch
end ;
function locase(ch : char) : char ;
{
search version - searches for the correct char
}
var
c : char ;
begin
for c := 'a' to 'z' do
if upcase(c) = ch then begin
locase := c ;
exit
end ;
{
if we get to here then ch was not an upper case letter
so do nothing
}
locase := ch
end ;
