Menu Pilihan 2

program Menu_Pilihan;
uses crt;
var
   pilihan  : byte;
   n,i,suku,m,o : integer;
   faktorial: real;
   a,b,c: integer;
   kali,x,y: integer;
begin
   repeat
     clrscr;textcolor(0);
     textbackground(BLUE);clrscr;
     window(12,7,68,19);textbackground(CYAN);clrscr;
     gotoxy(23,2);write('MENU PILIHAN');
     gotoxy(23,3);write('============');
     gotoxy(3,4);
     write('1. Menghitung Faktorial');
     gotoxy(3,5);
     write('2. Menentukan Suku ke-N dari Barisan : 3,6,9,36..');
     gotoxy(3,6);
     write('3. Menghitung M x N Menggunakan Operator +');
     gotoxy(3,7);
     write('4. Menentukan Barisan Fibbonancy');
     gotoxy(3,8);
     write('0. Keluar');
     gotoxy(3,10);
     write('Pilihan Anda {0-4} : ');readln(pilihan);
     {validasi menu pilihan}
     while(pilihan < 0) or (pilihan > 4) do
     begin
       gotoxy(27,10);textcolor(RED);
       write('Salah Memilih Menu..Ulangi!');
       gotoxy(27,11);textcolor(15);
       write('Tekan Enter untuk Melanjutkan');
       readln;
       gotoxy(27,11);clreol;gotoxy(24,10);clreol;
       readln(pilihan);
     end;
     case (pilihan) of
       1 : begin
             clrscr;
               gotoxy(19,2);write('Menghitung Faktorial');
               gotoxy(19,3);write('====================');
               gotoxy(10,4);
               write('Masukan Harga N = ');readln(n);
               {validasi harga n}
               while(n < 0) or (n > 20) do
                 begin
                   gotoxy(10,5);textcolor(RED);
                   write('Harga N antara 0 sampai 20.. Ulangi!');
                   gotoxy(10,6);textcolor(15);
                   write('Tekan Enter untuk Melanjutkan');
                   readln;
                   gotoxy(10,5);clreol;gotoxy(10,6);clreol;
                   gotoxy(28,4);clreol;
                   textcolor(0);readln(n);
                 end;
               if(n=0) or (n=1)
                 then
                   faktorial:=1
                 else
                 begin
                   faktorial:=n;
                   for i:= (n-1) downto 2 do
                     faktorial:=faktorial*i;
                 end;
               gotoxy(10,5);
               write('Faktorial dari ',n,' = ');
               textcolor(RED);write(faktorial:0:0);
               gotoxy(15,11);textcolor(15);
               write('Tekan Enter untuk Melanjutkan');
               readln;
           end;
       2 : begin
             clrscr;
               gotoxy(5,5);
               write('Menentukan Suku ke-N dari Barisan : 3,6,9,36..');
               gotoxy(5,6);
               write('==============================================');
               gotoxy(5,7);
               write('Masukan Harga N : ');readln(n);
               if(n=1)
                 then
                   suku:=3
                   else
                   begin
                     suku:=3;
                     for i := 2 to n do
                     begin
                       if(i mod 2=0)
                         then
                           suku := suku * i
                         else
                           suku := suku + i
                       end;
                   end;
                 gotoxy(5,8);
                 write('Suku ke-',n,'  : ');
                 textcolor(RED);write(suku);
                 gotoxy(15,11);textcolor(15);
                 write('Tekan Enter untuk Melanjutkan');
             readln;
           end;
       3 : begin

             clrscr;
               gotoxy(9,2);write('Menghitung M x N menggunakan operator +');
               gotoxy(9,3);write('=======================================');
               gotoxy(5,4);
               write('Masukan harga M = ');readln(m);
               gotoxy(5,5);
               write('Masukan harga N = ');readln(n);
               if(m=0)or(n=0)
                then
                  kali:=0
                else
               if(m<0)or(m>0)and(n>0)
                  then
                   kali:=m;
                   for i:=2 to n do
                   kali:=kali+m;
                  if (m>0) and(n<0)
                    then
                     begin
                      kali:=n;
                      for i:=2 to n do
                      kali:= kali+n;
                     begin
                      x := -m;
                      y := -n;
                      kali := x;
                      for i := 2 to y do
                      kali := kali +x;
                    end;
                  end;
             gotoxy(5,6);
             write(m,' x ',n,' = ');textcolor(RED);
             write (kali);
             gotoxy(15,11);textcolor(15);
             write('Tekan Enter untuk Melanjutkan');
             readln;
           end;
       4 : begin
             clrscr;
               gotoxy(15,2);write('Menentukan Barisan Fibbonancy');
               gotoxy(15,3);write('=============================');
               gotoxy(5,5);
               write('Masukkan nilai a = ');readln(a);
               gotoxy(5,6);
               write('Masukkan nilai b = ');readln(b);
               c := 0;
               gotoxy(5,7);
               write('Masukkan banyaknya angka : ');
               readln(n);
               gotoxy(5,8);write('Deret Fibonacci : ',a,' ',b,' ');textcolor(RED);
               for i := 1 to n do
               begin
               c := a + b;
               a := b;
               b := c;
               write(c, ' ');textcolor(RED);
               end;
               gotoxy(15,11);textcolor(15);
               write('Tekan Enter untuk Melanjutkan');
               readln;
               end;
     end;
   until(pilihan = 0);
end.