Turbo Pascal 5.5

Version of implementation Turbo Pascal of programming language Pascal

Turbo Pascal 5.5 was released on May 2, 1989.

Implemented language provided next major enhancement — basic support for object-oriented programming, including the concept of classes, static and dynamic objects, constructors and destructors and inheritance.

As for the interface, it finally introduced the distinctive blue full-screen user interface with pull-down menus, used in all later Turbo products. The IDE provided two more important features — step-by-step debugger and context-sensitive help with description of all built-in functions and possibility of copying fragments of code from help window and pasting it to your code.

Turbo Pascal 5.5: general view

Examples:

Fibonacci numbers - Pascal (58):

This example uses recursive definition of Fibonacci numbers.

program fibonacci;

function fib(n:integer): integer;
begin
    if (n <= 2) then
        fib := 1
    else
        fib := fib(n-1) + fib(n-2);
end;

var
    i:integer;

begin
    for i := 1 to 16 do
        write(fib(i), ', ');
    writeln('...');
end.

Hello, World! - Pascal (57):

program helloworld;

begin
    writeln('Hello, World!');
end.

Factorial - Pascal (96):

This example is exactly the same as main recursive example for Pascal implementations, except for that it uses real data type to store factorial values. Command writeln(f:-1:0) outputs the floating point number f with 0 digits after decimal point and left-justifies it.

program factorial;

function fact(n: integer): real;
begin
    if (n = 0) then
        fact := 1
    else
        fact := n * fact(n - 1);
end;

var
    n: integer;

begin
    for n := 0 to 16 do
        writeln(n, '! = ', fact(n):-1:0);
end.

Factorial - Pascal (44):

This example uses recursive factorial definition.

Note that this example works in all given implementations of Pascal, but it produces slightly different results. In gpc everything works perfectly. Turbo Pascal and Free Pascal have arithmetic overflow for factorial of numbers greater than 12, but Free Pascal reports an error:

13! = Runtime error 215 at $004013C7
$004013C7
$00401449
$004063E0

while Turbo Pascal doesn’t detect the error and simply prints wrong values:

13! = 1932053504
14! = 1278945280
15! = 2004310016
16! = 2004189184

This example doesn’t work in Turbo Pascal 3.0 and earlier due to absence of longint datatype in these versions.

program factorial;

function fact(n: integer): longint;
begin
    if (n = 0) then
        fact := 1
    else
        fact := n * fact(n - 1);
end;

var
    n: integer;

begin
    for n := 0 to 16 do
        writeln(n, '! = ', fact(n));
end.