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-rw-r--r--pascal.html.markdown86
1 files changed, 77 insertions, 9 deletions
diff --git a/pascal.html.markdown b/pascal.html.markdown
index 4144f900..28dcc10f 100644
--- a/pascal.html.markdown
+++ b/pascal.html.markdown
@@ -25,6 +25,10 @@ to compile and run a pascal program you could use a free pascal compiler. [Downl
//name of the program
program learn_pascal; //<-- dont forget a semicolon
+const
+ {
+ this is where you should declare constant values
+ }
type
{
this is where you should delcare a custom
@@ -55,17 +59,71 @@ var
//or this
var a,b : integer;
```
+
```pascal
program Learn_More;
//Lets learn about data types and their operations
+const
+ PI = 3.141592654;
+ GNU = 'GNU's Not Unix';
+ // constants are conventionally named using CAPS
+ // their values are fixed and cannot be changed during runtime
+ // holds any standard data type (integer, real, boolean, char, string)
+
+type
+ ch_array : array [0..255] of char;
+ // arrays are new 'types' specifying the length and data type
+ // this defines a new data type that contains 255 characters
+ // (this is functionally equivalent to a string[256] variable)
+ md_array : array of array of integer;
+ // nested arrays are equivalent to multidimensional arrays
+ // can define zero (0) length arrays that are dynamically sized
+ // this is a 2-dimensional array of integers
+
//Declaring variables
-var
- int : integer; // a variable that contains an integer number data types
- ch : char; // a variable that contains a character data types
- str : string; // a variable that contains a string data types
- r : real; // a variable that contains a real number data types
- bool : boolean; //a variables that contains a Boolean(True/False) value data types
+var
+ int, c, d : integer;
+ // three variables that contain integer numbers
+ // integers are 16-bits and limited to the range [-32,768..32,767]
+ r : real;
+ // a variable that contains a real number data types
+ // reals can range between [3.4E-38..3.4E38]
+ bool : boolean;
+ // a variable that contains a Boolean(True/False) value
+ ch : char;
+ // a variable that contains a character value
+ // char variables are stored as 8-bit data types so no UTF
+ str : string;
+ // a non-standard variable that contains a string value
+ // strings are an extension included in most Pascal compilers
+ // they are stored as an array of char with default length of 255.
+ s : string[50];
+ // a string with maximum length of 50 chars.
+ // you can specify the length of the string to minimize memory usage
+ my_str: ch_array;
+ // you can declare variables of custom types
+ my_2d : md_array;
+ // dynamically sized arrays need to be sized before they can be used.
+
+ // additional integer data types
+ b : byte; // range [0..255]
+ shi : shortint; // range [-128..127]
+ smi : smallint; // range [-32,768..32,767] (standard Integer)
+ w : word; // range [0..65,535]
+ li : longint; // range [-2,147,483,648..2,147,483,647]
+ lw : longword; // range [0..4,294,967,295]
+ c : cardinal; // longword
+ i64 : int64; // range [-9223372036854775808..9223372036854775807]
+ qw : qword; // range [0..18,446,744,073,709,551,615]
+
+ // additional real types
+ rr : real; // range depends on platform (i.e., 8-bit, 16-bit, etc.)
+ rs : single; // range [1.5E-45..3.4E38]
+ rd : double; // range [5.0E-324 .. 1.7E308]
+ re : extended; // range [1.9E-4932..1.1E4932]
+ rc : comp; // range [-2E64+1 .. 2E63-1]
+
Begin
int := 1;// how to assign a value to a variable
r := 3.14;
@@ -76,19 +134,28 @@ Begin
//arithmethic operation
int := 1 + 1; // int = 2 overwriting the previous assignment
int := int + 1; // int = 2 + 1 = 3;
- int := 4 div 2; //int = 2 a division operation which the result will be floored
+ int := 4 div 2; //int = 2 division operation where result will be floored
int := 3 div 2; //int = 1
int := 1 div 2; //int = 0
bool := true or false; // bool = true
bool := false and true; // bool = false
bool := true xor true; // bool = false
-
+
r := 3 / 2; // a division operator for real
- r := int; // you can assign an integer to a real variable but not the otherwise
+ r := int; // can assign an integer to a real variable but not the reverse
c := str[1]; // assign the first letter of str to c
str := 'hello' + 'world'; //combining strings
+
+ my_str[0] := 'a'; // array assignment needs an index
+
+ setlength(my_2d,10,10); // initialize dynamically sized arrays: 10×10 array
+ for c := 0 to 9 do // arrays begin at 0 and end at length-1
+ for d := 0 to 9 do // for loop counters need to be declared variables
+ my_2d[c,d] := c * d;
+ // address multidimensional arrays with a single set of brackets
+
End.
```
@@ -136,3 +203,4 @@ Begin // main program block
End.
```
+