Pascal is a procedural programming language that was designed to encourage good programming practices and readability. It is widely used in education and scientific computing for tasks such as numerical analysis, data processing, and simulation.
Variables in Pascal are declared using the var keyword. Pascal supports static typing, so you need to specify the type of the variable.
var
name: string;
age: integer;
pi: double;
Functions in Pascal are declared using the function keyword followed by the function name and parameters. Pascal supports nested functions, which are functions that are defined inside other functions.
function greet(name: string): string;
begin
greet := 'Hello, ' + name + '!';
end;
writeln(greet('John'));
var
add: function(a, b: integer): integer;
add := function(a, b: integer): integer
begin
add := a + b;
end;
writeln(add(2, 3));
Pascal supports for, while, and repeat until loops, as well as the if, else if, and else statements.
var
numbers: array[1..5] of integer;
i: integer;
numbers := (1, 2, 3, 4, 5);
for i := 1 to 5 do
writeln(numbers[i]);
i := 0;
while i < 5 do
begin
writeln(i);
i := i + 1;
end;
i := 0;
repeat
writeln(i);
i := i + 1;
until i >= 5;
Pascal supports if, else if, and else statements, as well as the ternary operator (in some dialects).
var
age: integer;
result: string;
age := 30;
if age < 18 then
writeln('You are too young to vote.')
else if age < 21 then
writeln('You can vote, but not drink.')
else
writeln('You can vote and drink.');
if age >= 18 then
result := 'You are an adult'
else
result := 'You are not an adult';
writeln(result);
Pascal provides several ways to read and write files. You can use the Assign, Rewrite, Reset, Write, Read, and Close functions to create, read, write, and delete files.
var
fileHandle: text;
content: string;
Assign(fileHandle, 'example.txt');
Rewrite(fileHandle);
Write(fileHandle, 'Hello, world!');
Close(fileHandle);
Reset(fileHandle);
Read(fileHandle, content);
Close(fileHandle);
writeln(content);
Erase(fileHandle);