💾 Archived View for gem.sdf.org › s.kaplan › cheatsheets › programming-languages › pascal.md captured on 2024-03-21 at 15:46:55.
⬅️ Previous capture (2023-09-28)
-=-=-=-=-=-=-
# Pascal Cheatsheet 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. ## Unique Features - Strong typing - Structured programming constructs - Modular programming - Pointers and dynamic memory allocation - Object-oriented programming (in some dialects) ## Variables 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 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));
## Loops 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;
## Conditionals 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);
## File Manipulation 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);
## Resources - [Free Pascal Documentation](https://www.freepascal.org/docs.html) - [Pascal Style Guide](https://www.cs.cornell.edu/courses/cs312/2002sp/styleguide/pascal.html) - [Pascal Tutorials](https://www.tutorialspoint.com/pascal/index.htm) - [Pascal Programming for Schools](http://pascal-programming.info/) - [Pascal Compiler Online](https://www.onlinegdb.com/online_pascal_compiler)