Bài 14.

a)program Taylor;
uses crt;
var n,i,a:longint; s:STRING;
begin
clrscr;
   write('n=');readln(n);
   write('s=');readln(s);
   for i:=1 to length(s) do
      begin
         a:=ord(s[i])+n;
         if a>122 then write(chr(97+(a-123))) else  write(chr(a));
      end;
readln
end.

b)program Taylor;
uses crt;
var n,i,a,b:longint; s:STRING;
begin
clrscr;
   write('n=');readln(n);
   write('s=');readln(s);
   for i:=1 to length(s) do
      begin
         a:=ord(s[i])-n;
         if a<97 then write(chr(123-(97-a))) else  write(chr(a));
      end;
readln
end.

Bài 15.

a)program Taylor;
uses crt;
var i:longint; s:STRING;
begin
clrscr;
   write('s=');readln(s);
   for i:=1 to length(s) do
         if s[i]<>'z' then write(chr(ord(s[i])+1)) else write('a');
readln
end.
b)program Taylor;
uses crt;
var i:longint; s:STRING;
begin
clrscr;
   write('s=');readln(s);
   for i:=1 to length(s) do
         if s[i]<>'a' then write(chr(ord(s[i])-1)) else write('z');
readln
end.