In Pascal a program must be declared to have input in the program header.

    The Readln statement fetches data from the person using the program and will convert typed characters into numbers if necessary.

    The input can come from punched cards, keyboard, or even a file.

program SimpleProgram (input, output);
var    Age: integer;
begin
    write ('How old are you? ');
    readln (Age);
    write ('You are ')
    write (Age)
    writeln (' years old ')
end.

    It is possible to have more than one number (or other items) entered with a single Readln statement.

program SimpleProgram (input, output);
var    Age, OtherNumber: integer;
begin
    write ('How old are you? ');
    readln (Age, OtherNumber);
    write ('You are ')
    write (Age)
    writeln (' years old ')
    write ('Your other number is ')
    writeln (OtherNumber)
end.

    Pascal expects each input to be of the correct type. Incorrect types may crash the program.

program SimpleProgram (input, output);
var    Age: intger;
       OtherNumber: real;
begin
    write ('How old are you? ');
    readln (Age, OtherNumber);
    write ('You are ')
    write (Age)
    writeln (' years old ')
    write ('Your other number is ')
    writeln (OtherNumber)
end.

    Notice that the reserved word var is used only once and a semicolon separator is used between the declarations.

    In Pascal any extra information on a card (or typed entry) that isn’t specifically asked for in the Readln statement is discarded and ignored.

    You may use the Pascal statement Read to get one character at a time.

program SimpleProgram (input, output);
var    FirstCharacter, SecondCharacter, ThirdCharacter, LastCharacter: char;
begin
    write ('What is your password? ');
    read (FirstCharacter, SecondCharacter, ThirdCharacter, LastCharacter);
    write ('Your secret password is ')
    writeln (FirstCharacter, SecondCharacter, ThirdCharacter, LastCharacter)
end.