Pascal Cheat Sheet

program HelloWorld;
begin
  WriteLn('Hello, World!');
end.

program MyProgram;
uses SysUtils;

var
  x: Integer;

begin
  x := 10;
  WriteLn(x);
end.

// Single line comment

(* Multi-line
   comment *)

{ Alternative
  comment style }

unit MyUnit;

interface
  function Add(a, b: Integer): Integer;

implementation
  function Add(a, b: Integer): Integer;
  begin
    Result := a + b;
  end;

end.

var
  age: Integer;
  name: String;
  price: Real;
  flag: Boolean;

var
  count: Integer = 0;
  message: String = 'Hello';

const
  PI = 3.14159;
  MAX_SIZE = 100;

type
  TAge = 0..120;
  TName = String[50];
  TStatus = (Active, Inactive, Pending);

Integer, Real, Boolean, Char, String
Byte, Word, LongInt, Double, Extended

result := a + b;  // Addition
result := a - b;  // Subtraction
result := a * b;  // Multiplication
result := a div b; // Integer division
result := a mod b; // Modulo
result := a / b;   // Real division

if a = b then   // Equal
if a <> b then  // Not equal
if a > b then   // Greater
if a < b then   // Less
if a >= b then  // Greater or equal
if a <= b then  // Less or equal

if (a > 0) and (b > 0) then
if (a > 0) or (b > 0) then
if not flag then
if (a > 0) xor (b > 0) then

x := 10;           // Assignment
x := x + 1;        // Increment
Inc(x);            // Increment by 1
Dec(x);            // Decrement by 1
Inc(x, 5);         // Increment by 5

if age >= 18 then
  WriteLn('Adult')
else
  WriteLn('Minor');

if score >= 90 then
  grade := 'A'
else if score >= 80 then
  grade := 'B'
else if score >= 70 then
  grade := 'C'
else
  grade := 'F';

case dayOfWeek of
  1: WriteLn('Monday');
  2: WriteLn('Tuesday');
  3..5: WriteLn('Midweek');
  6, 7: WriteLn('Weekend');
else
  WriteLn('Invalid');
end;

if x > 0 then
begin
  WriteLn('Positive');
  Inc(count);
end;

for i := 1 to 10 do
  WriteLn(i);

for i := 10 downto 1 do
  WriteLn(i);

while count < 10 do
begin
  WriteLn(count);
  Inc(count);
end;

repeat
  WriteLn(count);
  Inc(count);
until count > 10;

for i := 1 to 100 do
begin
  if i = 50 then Break;  // Exit loop
  if i mod 2 = 0 then Continue; // Skip even
  WriteLn(i);
end;

procedure Greet(name: String);
begin
  WriteLn('Hello, ', name, '!');
end;

// Call
Greet('Alice');

function Add(a, b: Integer): Integer;
begin
  Result := a + b;
end;

// Call
x := Add(5, 3);

procedure Swap(var a, b: Integer);
var temp: Integer;
begin
  temp := a;
  a := b;
  b := temp;
end;

function Power(base: Integer; exp: Integer = 2): Integer;
begin
  Result := Round(Exp(exp * Ln(base)));
end;

y := Power(5);     // 25
z := Power(2, 3);  // 8

var
  numbers: array[1..10] of Integer;
  names: array[0..4] of String;

numbers[1] := 100;
WriteLn(numbers[1]);

var
  arr: array of Integer;
begin
  SetLength(arr, 5);
  arr[0] := 10;
end;

type
  TPerson = record
    name: String;
    age: Integer;
  end;

var
  person: TPerson;
begin
  person.name := 'John';
  person.age := 30;
end;

var
  people: array[1..10] of TPerson;
begin
  people[1].name := 'Alice';
  people[1].age := 25;
end;

var s: String;
s := 'Hello';
s := s + ' World';  // Concatenation

Length(s)          // String length
Pos('ll', s)       // Find substring
Copy(s, 1, 5)      // Extract substring
UpCase(s)          // Uppercase
LowerCase(s)       // Lowercase

IntToStr(42)       // Integer to string
StrToInt('42')     // String to integer
FloatToStr(3.14)   // Float to string
StrToFloat('3.14') // String to float