Question

When I compile the following code, I get errors. I don’t understand some of them.

Code

program Lasagna;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}{$IFDEF UseCThreads}
  cthreads,
  {$ENDIF}{$ENDIF}
  Classes, SysUtils
  { you can add units after this };

{$R *.res}
type
  TVehicle = record
    kindOfVehicle : String[30];
    numberOfWheels : Integer;
    horsePower : Real;
  end;

var
  F: file of TVehicle;
  Vehicle : Array [1..3] of TVehicle;
  index : Integer;

begin
     writeln('A RECORD OF DIFFERENT KIND OF VEHICLES.');
     writeln('---------------------------------------');
     writeln;

     AssignFile(F,'C:/Users/W/Desktop/CarRecord.dat');
     writeln('Searching for file.');
     if FileExists('C:/Users/W/Desktop/CarRecord.dat') then
        begin
          writeln('File found. Opening file.');
          Rewrite(F);
          writeln('File ready.');
          writeln;
          writeln;

          for index:=0 to 3 do
          begin
            writeln('Enter the following details for vehicle no. ',index);
            write('Kind of Vehicle: ');
            readln(Vehicle[index].kindOfVehicle);
            write(F,Vehicle[index].kindOfVehicle);//line 45: this is a string so why do I get an error?**

            {Do NOT use writeln() when writing to random access files.}

            write('Number of Wheels: ');
            readln(Vehicle[index].numberOfWheels);
            write(F,IntToStr(Vehicle[index].numberOfWheels));//line 51: The int is converted to string, so i shouldn't get an error?

            write('Horse Power of Vehicle: ');
            readln(Vehicle[index].horsePower);
            write(F, RealToStr(Vehicle[index].horsePower));//line 55:  
            end;

          writeln('Done. Closing File.');
          CloseFile(F);
        end
     else
         Rewrite(F);
         CloseFile(F);
         writeln('File Not Found.');

     Writeln('Press ANY key to close the program.');
     Readln;
end.

Errors

Compiling Lasagna.lpr

Lasagna.lpr(45,49) Error: Incompatible types: got “ShortString”
expected “TVehicle”

Lasagna.lpr(51,60) Error: Incompatible types: got “AnsiString”
expected “TVehicle”

Lasagna.lpr(55,59) Error: Incompatible types: got “AnsiString”
expected “TVehicle”

Lasagna.lpr(70) Fatal: There were 3 errors compiling module, stopping

Answer 1

In line 21, you are declaring F as “file of TVehicle”. So, you should write TVehicle data to it, not strings.