{***Name: Winnie Leung   Class: F.4CA    Class no.: 22 ***}
{***This program is using arrays to stimulate the processing
of electric bills of an electronic power company ***}
program POWBILL (input, output);
uses wincrt;
const rate = 8.83;
var choice, diff, ac, n : integer;
       month : string;
       powread : array[1..12] of integer;
       cname : string;
       amt : real;
       mth : array[1..12] of string;

        (*** procedure ***)
          procedure  accdata (acc :integer; var ccname:string);
            begin           
              If acc = 12836 then   
              ccname := 'Peggy So';
              diff:= 60;
            end;

       (*** Main Program ***)
begin
    writeln('RUN');
    writeln('MENU');
    writeln('(1)  Enter monthly readings');
    writeln('(2)  Search customer records');
    writeln('Choose a number for your choice.');
    writeln;
    write('Choice : ');
    readln(choice);  
    mth[1]   := 'JANUARY 2000';
    mth[2]   := 'FEBRUARY 2000';
    mth[3]   := 'MARCH 2000';
    mth[4]   := 'APRIL 2000';
    mth[5]   := 'MAY 2000';
    mth[6]   := 'JUNE 2000';
    mth[7]   := 'JULY 2000';
    mth[8]   := 'AUGUST 2000';
    mth[9]   := 'SEPTEMBER 2000';
    mth[10]  := 'OCTOBER 2000';
    mth[11]  := 'NOVEMBER 2000';
    mth[12]  := 'DECEMBER 2000';
    If choice = 1 then
      begin
        write('Customer name : ');
        readln(cname);
        write('Account number : ');
        readln(ac);
        write('Billing month : ');
        readln(month);
        n :=1 ;
          repeat  n:=n+1  until mth[n]=month;      
            write('Last month reading : ');
            readln(powread[n- 1]);
            write('This month reading : ');
            readln(powread[n]);
            writeln;
            writeln('Electricity is charged at $', rate:4:2, ' per unit (kilo watt hour)');
            writeln;
            writeln('Monthly Electric Bill');
            writeln;
            writeln('Account number : ', ac);
            diff := powread[n] - powread[n - 1];
            writeln('Unit of electricity consumed this month : ', diff);
            amt := diff * rate;
            writeln('This month electric charge : ', amt:0:2);
      end
    else
      begin
          write('Account number : ');
          readln(ac);
          accdata(ac, cname);
          writeln;      
          writeln('Customer name : ', cname);
          writeln('Unit of electricity consumed this month : ', diff);
          amt := diff * rate;
          writeln('This month electric charge : ', amt:0:2);
      end;
      
end.