programming-for-dummies

578
Declaring Variables
If you only want to store a single character, you can use the Char keyword,
such as
Var
Variablename1 : Char;
To assign values to a variable in Pascal, use the colon and the equal sign
symbols, such as :=, instead of just the equal sign (=) like other programming
languages.
Declaring integer data types
Whole numbers represent integers such as 349, –152, or 41. A whole number
can be positive or negative. The most common type of integer data type is
Integer and is used as follows:
Var
Variablename1 : Integer;
To accept different ranges of integer values, Pascal offers several integer
data types. For example, if a variable needs only to hold a positive value, you
can declare it as a Byte data type, such as
Var
Variablename1 : Byte;
Besides limiting the range of integer values, different integer data types also
require different amounts of memory to store that data. The greater the
range of values you need to store, the more memory needed (measured in
bytes). The smaller the range of values, the less memory required. Table 4-1
shows different integer data types, the memory needed, and the range of
values they can hold.
Table 4-1
Pascal Integer Data Types
Data Type Number of Bytes Range
Byte 1 0 to 255
ShortInt 1 –128 to 127
Word 2 0 to 65,535
SmallInt 2 –32,768 to 32,767
Integer 4 –2,147,483,648 to 2,147,483,647
LongWord 4 0 to 4,294,967,295
Int64 8 –9,223,372,036,854,775,808 to
9,223,372,036,854,775,807