Turbo Pascal is an IDE with its own compiler, created by Borland Corporation (name Borland Pascal is used to refer to more high-end product).
Turbo Pascal was first released in 1983, and for that time it was an outstanding thing — it was an IDE which combined editor, one-pass compiler and linker which produced .com executables (.exe executables since version 4). “Turbo” emphasized the speed of both compilation and resulting program execution.
Turbo Pascal was widely used in education.
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 data type in these versions.
In GNU Pascal this program works without any problems.
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. 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. 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. program helloworld; begin writeln('Hello, World!'); end. Pascal has built-in complex data type complex , but using it is inconvenient in this case, because writeln can’t output complex numbers directly, and functions Re and Im would have to be used. In this example calculations are done in real numbers. Library function halt (added in Extended Pascal) exits current block (in later versions it is replaced with exit ).
program Quadratic; var A,B,C,D: integer; begin write('A = '); readln(A); if (A=0) then begin writeln('Not a quadratic equation.'); halt; end; write('B = '); readln(B); write('C = '); readln(C); D := B*B-4*A*C; if (D=0) then begin writeln('x = ',-B/2.0/A); halt; end; if (D>0) then begin writeln('x1 = ',(-B+Sqrt(D))/2.0/A); writeln('x2 = ',(-B-Sqrt(D))/2.0/A); end else begin writeln('x1 = (',-B/2.0/A,',',Sqrt(-D)/2.0/A,')'); writeln('x2 = (',-B/2.0/A,',',-Sqrt(-D)/2.0/A,')'); end; end. This example processes the string char by char, and works with ASCII-codes to figure out whether they are lower- or uppercase letters. ord returns ASCII-code of a character, while chr converts given ASCII-code into a character. String capacity is omitted and thus set to 255 by default.
Note that in Turbo Pascal series this program works only with Turbo Pascal 4.0 and higher due to the fact that earlier versions didn’t have char datatype.
program Camelcase; var text, cc: string; c: char; i: integer; lastSpace: boolean; begin readln(text); lastSpace := true; cc := ''; for i := 1 to Length(text) do begin c := text[i]; if ((c >= #65) and (c #90)) or ((c >= #97) and (c #122)) then begin if (lastSpace) then begin if ((c >= #97) and (c #122)) then c := chr(ord(c) - 32); end else if ((c >= #65) and (c #90)) then c := chr(ord(c) + 32); cc := cc + c; lastSpace := false; end else lastSpace := true; end; writeln(cc); end. This example is similar to previous one, but uses sets of characters for letter check. This makes the code more readable.
Note that in Turbo Pascal series this program works only with Turbo Pascal 4.0 and higher due to the fact that earlier versions didn’t have char datatype.
program Camelcase; var text, cc: string[100]; c: char; i: integer; lastSpace: boolean; upper, lower: set of char; begin upper := ['A'..'Z']; lower := ['a'..'z']; readln(text); lastSpace := true; cc := ''; for i := 1 to Length(text) do begin c := text[i]; if (c in lower) or (c in upper) then begin if (lastSpace) then begin if (c in lower) then c := chr(ord(c) - 32); end else if (c in upper) then c := chr(ord(c) + 32); cc := cc + c; lastSpace := false; end else lastSpace := true; end; writeln(cc); end.