From e533369df895fc5f2fd3a034b0fb53d84672f877 Mon Sep 17 00:00:00 2001 From: Keith Miyake Date: Tue, 2 Oct 2018 13:55:35 -0700 Subject: [pascal/en] add functions/procedures --- pascal.html.markdown | 44 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) diff --git a/pascal.html.markdown b/pascal.html.markdown index 6877afef..4144f900 100644 --- a/pascal.html.markdown +++ b/pascal.html.markdown @@ -3,6 +3,7 @@ language: Pascal filename: learnpascal.pas contributors: - ["Ganesha Danu", "http://github.com/blinfoldking"] + - ["Keith Miyake", "https://github.com/kaymmm"] --- @@ -92,5 +93,46 @@ End. ``` ```pascal +program Functional_Programming; -``` \ No newline at end of file +Var + i, dummy : integer; + +function factorial_recursion(const a: integer) : integer; +{ recursively calculates the factorial of integer parameter a } + +// Declare local variables within the function +// e.g.: +// Var +// local_a : integer; + +Begin + If a >= 1 Then + // return values from functions by assigning a value to the function name + factorial_recursion := a * factorial_recursion(a-1) + Else + factorial_recursion := 1; +End; // terminate a function using a semicolon after the End statement. + +procedure get_integer(var i : integer; dummy : integer); +{ get user input and store it in the integer parameter i. + parameters prefaced with 'var' are variable, meaning their value can change + outside of the parameter. Value parameters (without 'var') like 'dummy' are + static and changes made within the scope of the function/procedure do not + affect the variable passed as a parameter } + +Begin + write('Enter an integer: '); + readln(i); + dummy := 4; // dummy will not change value outside of the procedure +End; + +Begin // main program block + dummy := 3; + get_integer(i, dummy); + writeln(i, '! = ', factorial_recursion(i)); + // outputs i! + writeln('dummy = ', dummy); // always outputs '3' since dummy is unchanged. +End. + +``` -- cgit v1.2.3